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Almonds

Alternaria Leaf Spot

Symptoms of Alternaria leaf spot appear as lesions with tan spots on the leaves. The centers of these lesions become black with fungal sporulation. This infection can lead to tree death within 3-4 years of the first serious outbreak. Orchards in high humidity areas result in the largest yield loss, often in excess of 50%.^[1] Yield loss tends to rise every year as the tree becomes weaker each year after infection. Three fungicide applications can achieve 60-80% control of leaf spot^[2]

Anthracnose

Anthracnose was not seen on California almonds until the early 1990s. By 1996 it was widespread and causing severe yield losses throughout the state ^[3]. Typical losses in 1996 were 10-15% of the almond crop with severely affected crops incurring losses of 25% ^[4]. Under wet conditions, orange spore masses are produced and appear as visible droplets. Lesions on mature fruit are rusty orange and gum profusely. Once this diseased fruit die and they become the mummies that remain on the tree. The pathogen overwinters in these mummies. ^[3] 80-90% control can be achieved by applying fungicides to protect the crop before rains begin. The California Department of Pesticide Regulation has estimated that without the fungicides to control anthracnose the state’s almond production would drop 15-30% ^[5]

Brown Rot

Damage from brown rot occurs several years after the infection strikes. The primary symptom is fruiting spur loss. Brown rot was first discovered on California almonds in the late 19th century and currently affects most almond producing areas of California. Brown rot can be control by using fungicides through bloom in order to protect the flower parts brown rot attacks. ^[6] Experiments have demonstrated that 44% of twigs were infected with brown rot when crops were left untreated compared to only 4% when the crop was treated^[7].

Crown and Root Rot

Crown and root rot of almonds is caused by at least 14 different Phytophthora species. Risk of root or crown infection is greatest during cool to moderate temperatures with prolonged or frequent soil saturation. ^[6] A tree infected with Phytophthora can either undergo a period of slow decline that may last years or it can suddenly collapse and die in spring with the advent of warm weather.^[8] Eventually, leaves drop, terminal shoots die back, followed by death of the tree. Once in the root or crown the infection, may extend into the crown, trunk, or branches.^[8] Currently, crown and root rot are a problem affecting 20% of California’s almond orchards with potential yield losses of 50%.^[6]

Green Fruit rot

Green fruit rot can be found throughout virtually all almond producing regions of California ^[9]. Green rot is typically controlled by the other fungicides applied to control the fungal diseases that occur during blooming. It is only when cooler temperatures and heavy moisture is present that almond growers are recommended to make fungicide applications specifically for the disease. ^[8] When left untreated green fruit rot can cause up to a 10% yield loss ^[6].

Leaf Blight

Leaf blight of almonds was first discovered in 1950, and by 1983 it had spread throughout the Sacramento Valley. ^[8]^[9] Almond leaf blight is characterized by the death of leaves throughout the summer.^[10] The fungus interferes with water conduction in the leaf. In fall and winter, dormant buds are killed by an extension of the lesion and in the spring, flowers are killed.^[10] Repeated attacks of leaf blight, though rarely killing more than 20% of the leaves, ultimately reduce tree vigor. Experiments have shown that the use of ziram and captan can reduce the incidence of leaf blight by 75-80% in treated trees. ^[10]

Rust

Almond rust is a disease of almond trees that is characterized by angular yellow leaf spots on upper leaf surfaces and rusty brown masses of spores on lower leaf surfaces ^[6]. It was first discovered in the upper Sacramento Valley area of California but now has subsequently spread throughout both the Sacramento and San Joaquin valley orchards ^[9]. It typically emerges in the summer and fall seasons and has been shown to cause extensive defoliation of trees in a rapid period of time ^[6]. Treatments of maneb and sulfur in the early season months (typically spring and summer) has been shown to significantly reduce incidence and severity of rust outbreaks ^[9] ^[3].

Scab

Almond scab was first documented in almond orchards in the 1950s. However it did not become a major diseases until the use of sprinkler irrigation became popular in the 1980s ^[9]. By the early 1990s almond scab could be found throughout California almond orchards. Scab infects leaves, fruit, and twigs in almonds causing dark spots to form. Scab lesions look greasy and oily. The major concern with almond scab is partial or complete defoliation of the tree.^[9] As with leaf blight use of captan and ziram has been shown to reduce total incidence of almond scab infection. ^[6]

Shot Hole

Shot hole affects almonds by disrupting both the leaves and the fruit of the plant. It can result in premature nut ripening and plant defoliation. In some occasions, especially when rain persists in the springtime, complete defoliation and tree weakening can occur. ^[6] Estimates have shown that approximately 80% of California’s almond acres are infected with this fungus ^[11]. A four year research project by the Almond Board of California determined that production losses could range from 50 to 75% from shot hole ^[9]. Captan in one to three applications has been used as the primary fungicide to combat this disease. It has been shown to reduce lesions per fruit by 96%. ^[12]

Apples

Spraying for control of fungal diseases of apples started in the U.S. somewhere between 1880 and 1905.

Apple Scab

Apple scab is caused by a fungus Venturia inaqualis. Mating among different strains of the fungus occurs shortly after leaf fall with spores developing in the fallen leaves during the winter. Spring rains cause spores to be forcibly discharged; they can be carried long distances by air currents to flowers, leaves, or young fruit ^[13]. The spores then continue to develop and are released over a period of 5-9 weeks ^[14]. These spores germinate and penetrate the outer layers of the plant, causing infection. The fungus grows beneath the cuticle and eventually ruptures to form dark green lesions. The number of lesions per leaf can be as few as 1-2 or there can be hundreds ^[14]. The USDA’s National Agricultural Pesticide Impact Assessment Program estimated that 100% of eastern apple orchards are stricken with apple scab and that without fungicide treatments yield losses would be as high as 90% ^[15]. In the western orchards 52% are infected and apple yield loss can be as high as 22% ^[11]. However with the use of fungicides experiments have shown heavy reductions in the percentage of infected apples. One study was able to reduce the incidence from 77% to 2% ^[16].

Bitter Rot

Bitter rot is a major disease in the Southeast U.S. in the summer months if the weather is hot and damp ^[17]. The organism has a short incubation period and as a result epidemics of bitter rot can develop rapidly. The presence of the disease is first indicated by the very small light brown sunken spots beneath the apple skin ^[18]. As the fungus grows and invades more of the apple tissue, the area becomes engorged until the entire apple is rotted ^[19]. At the turn of the century Bordeaux mixture was the primary technique for controlling the disease and in the 1940s growers shifted to synthetic chemical use ^[18] ^[19]. Without the use of these fungicides is it estimated that apple yield loss due to bitter rot could be as high at 90% ^[15]

Black Pox

This disease primarily affects the southeastern portion of the United States and is known to infect the cultivars Rome Beauty, Grimes Golden, Delicious, York Imperial, and Golden Delicious. Lesions on twigs are well defined, conical, shiny black swellings and on the fruit itself they are black, spherical, slightly sunken spots. Severely affected leaves may die within 2 to 3 weeks of infection. Infected branches will grow poorly, lose their leaves early, and die. Black pox can be controlled with the same fungicide sprays that are used to treat scab ^[14].

Blossom-end rot

The first symptom of blossom-end rot is soft, wet, and reddish discolorations that appear in the late summer months. As the rot stops growing it will begin to dry out and appear sunken ^[14]. The affected fruit will often drop prematurely. Fungicide experiments have shown reduced incidence, from 5% to less than 0.5%, with treatment ^[20].

Brooks Fruit Spot

Brooks fruit spot is a minor disease of the apple and is found mostly throughout the Northeast and Mid-Atlantic regions. As the fruit first emerges the disease appears as dark green lesions on the fruit of the apple. As the apple begins to emerge these blemishes will grow and change to purple or green ^[14]. Brooks fruit spot is usually controlled with fungicides applied during the early cover-spray period. One study showed that apple orchards that were not treated with fungicides had 87% of their fruit infected with brooks fruit spot while only 1-6% of trees that were treated with fungicides showed symptoms of the disease ^[21].

Fire Blight

Fire blight was first described in New York in the late 1700s, and moved west with settlers, becoming established throughout North American apple production areas by the early 1900s. While fire blight has always been a concern in eastern apple production, severe outbreaks in the west in recent years have caused growers there to adopt more consistent and vigorous monitoring and management programs as well. ^[22] The disease can impact every part of the tree fruit to the trunk ^[14]. Infected trees may die within months or can linger for years with severely reduced yields. In addition to the scorched appearance (hence the name fire blight) of the plant parts, plant tissues infected with the fungus will exude milky or reddish-brown ooze. Initially copper sprays were used for fire blight control in the 1930s but this method had only limited success^[23]. In the 1950s streptomycin and oxytetracycline showed high success in controlling fire blight in comparison to copper. Since then streptomycin sprayed two to three times during blooming phase has become the treatment of choice.

Powdery Mildew

Powdery mildew is a common fungal infection of apples and can occur in almost any apple growing climate. The spores from fungi preserved over the winter are released from the unfolding leaves of the buds. The spores, carried by the wind, infect leaves, blossoms, and fruit ^[14]. The fungus spreads until it covers the whole leaf and then grows down twigs, covering them with a gray felt. This results in aborted blossoms, reduced finish quality, and reduced yield^[24]. The US Department of Agriculture has estimated that 40% of apple orchards in the East and 50% of apple orchards in the West are infected with powdery mildew ^[11]. Without control of the fungus yields would drop by 65% ^[15].

Quince Rust

Quince rust infects the fruit of the apple trees but does not affect the leaves. Quince rust spores infect cedar trees and create cylindrical galls from which emerge spore horns the following spring. These galls may produce spores for up to twenty years. Quince rust is economically important primarily when an extended wetting period with a mean temperature above 10 degrees Celsius occurs between the tight cluster and late pink bud stages. Under these conditions, economic losses may occur throughout large geographic areas ^[14]. Experiments with fungicide sprays have been shown to provide complete control of rust ^[25]

White Rot

White rot develops its name from the soft, watery, and light-colored rotted fruit that is left over after an apple is infected. The fungus survives from season to season in the dead bark and mummified fruit of the apple tree. Spores can survive in the dead bark for up to six years ^[26]. Growers are advised to treat for white rot once the sugar content of the fruit reaches approximately 10%. USDA estimates that 20% of apple orchards in eastern states are infected with the fungus and that without fungicide use yield losses would be 65%. ^[15].

Artichokes

California produces 100% of all artichoke crops in the U.S. 84% of this acreage is located near the cool, moist, coastal area of Monterey Bay. The climate there is ideal for artichoke production.

Powdery Mildew

In 1984, artichoke fields were reported to have been infected with powdery mildew for the first time. In the ensuing years the disease continued to reappear with each year the disease becoming more widespread than in the past ^[27]. The fungus colonizes the underside of leaves and the wind carries spores between fields ^[28]. Severely infected leaves will discolor, collapse, and dry up prematurely; thus reducing the plant’s photosynthetic area.

Currently, there are no registered fungicides that provide effective control of the disease in the coastal conditions of California. Sulfur is registered but it has been shown to be largely ineffective in controlling powdery mildew. For sulfur to be effective, it is critical that the ambient air temperature be warm. The cool and humid climate of the coastal region means sulfur is ineffective in controlling powdery mildew.^[27] As a result every year since 1987 California has requested the EPA grant emergency registration for fungicides to be used in controlling powdery mildew.

Asparagus

Crown Rot

Crown rot in asparagus was first reported in California in 1938 when California growers began to report a slimy, orange-yellow asparagus tissue with soft lesions causing post harvest losses of 20-30% ^[29] ^[30]. As lesions grow they eventually collapse and shrivel ^[31]. In the 1980s it was shown that fungicidal treatments of metalaxyl increased yields by 80% ^[30]. Today mefenoxam is the primary fungicide used for crown rot.

Purple Spot

Purple spot was first observed in the United States in the 1980s. Yield impact by this disease is delayed because the damage to fern growth does not impact current yields but instead impacts the future crop. Damage results in the defoliation of needles, reducing the flow of carbohydrates to the roots and subsequently lowering the next years yield by up to 52% ^[31]. In the spring spores produced from the previous year’s infected crops are spread by water and wind to new host plants.

The primary control of purple spot was EBDC fungicides until processors began to reject the use of EBDCs. As a result since 1990 exemptions for chlorothalonil and tebuconazole in Michigan have been granted by the EPA for use on asparagus. The fungicides are applied at the end of the harvest and chlorothalonil has been shown in experiments to reduce purple spot by 99% and increase yields by 36% ^[32]. This increase in yield as a result of purple spot control has been shown to translate into a net return of $200-400 per acre for asparagus growers ^[33].

Rust

Asparagus rust was first reported in the U.S. in 1896. It began on the asparagus crops of mostly northeastern states and began to move westward across the country ^[34]. For each successive year the disease was discovered in new western areas until in 1902 it was reported in California for the first time. Research to control the disease began with Bordeaux mixture experiments at the turn of the century. Copper and sulfur dust were tried as well but the success was very limited. Sulfur was the only one to have much success at all. ^[34] ^[35]. Rust resistant strains of asparagus were cultivated but by the 1940s and 1950s these strains of asparagus were no longer providing adequate levels of resistance ^[36]. In the 1950s zineb and mancozeb were developed as the primary means to control rust. Zineb reduced infection by 85% and mancozeb by 97% ^[37] ^[38]. By 1989 EBDC fungicides had become the most common fungicidal means to control rust on asparagus. However after EPA almost cancelled the use of EBDC’s on asparagus many processors decided they would not accept asparagus treated with EBDC’s despite the EPA allowing its use after review. This meant that many growers were left with no registered fungicide to use on asparagus. Since 1990 EPA has granted exemptions for tebuconazole, myclobutanil, and triadimefon for use on asparagus.

Bananas

Hawaii is the primary state in the U.S. where bananas are grown. The average yield is 15,000 pounds/acre. Approximately 600-800 plants are grown per acre. Planting occurs year round. Banana bunches are ready for harvest 12 to 15 months after initial planting ^[39]. On a banana plantation, plants can be seen at all stages of vegetative growth and fruit maturity year-round. Bananas can be harvested any day of the year.

Black Sigatoka

Black sigatoka as with yellow sigatoka was first documented in the Sigatoka valley of Fiji. It was first recorded in 1964 and being more virulent tended to displace yellow sigatoka in banana crops. Therefore yellow sigatoka is rarely found in locations where black sigatoka occurs ^[40]. Black sigatoka infection appears on the leaves of crops during the unfurling. Sigatoka spores will incubate on the leaves for up to six days before penetrating the leaf ^[40]. After this the infection will continue to colonize for a week before showing any symptoms on the plant. The initial symptoms are small spots on the underside of the leaves. This will appear 10-15 days after infection and will begin to grow and enlarge until they appear to be streaks of black on the leaves. This is what gives black sigatoka its alternate name of black leaf streak ^[40]. These streaks can dry out and collapse in less than day. This will affect growth and yield of the bananas by reducing the total photosynthetic area of the leaf ^[41]. However the largest impact on yields is through the toxins produced by black sigatoka that causes a premature ripening of the bananas. These prematurely ripened fruit cannot be sold and must simply be discarded.

Under normal conditions in Hawaii it is estimated that without control of black sigatoka yield losses would be 30% ^[11]. Sigatoka is controlled with a combination of protectant and systemic fungicides in order to prevent resistance from developing. Mancozeb is applied as the primary protectant and fenbuconazole, tebuconazole, and azoxystrobin are applied as systemic fungicides ^[41]. These fungicides are applied during the summer months ^[11].

Yellow Sigatoka

Yellow Sigatoka derives its name from the Sigatoka valley in Fiji. This was where the disease was first documented in 1912.Over the course of the first half of the 20th century the disease managed to spread to all major banana-producing countries of the world. It was first seen in Trinidad in 1934 and quickly spread to the mainland and up through Central America ^[42]. The disease can spread spores over 1,000 miles with wind currents. By 1936 experiments with Bordeaux mixture were developed to control the disease. The disease was first discovered in Hawaii in 1958.

Barley

The major barley producing states of the United States are Idaho, Minnesota, Montana, and North Dakota. These states make up 70% of barley production in America. This barley is principally used in malting and brewing. It is also in some areas used as a feed grain.

Barley scab

Outbreaks of barley scab (also known as fusarium head blight) occur usually when there are high moisture conditions during the flowering stages of barley development. The infected crops become bleached in color, shrunken, and discolored and will grow pink spore masses on the barley heads. The disease has the potential to destroy a crop within weeks ^[43]. The shrunken kernels can become so light that the wind can blow them away from the rest of the crop. In addition, barley scab produces toxins that severely reduce the value of the harvested barley. This toxin, deoxynivalenol, also known as vomitoxin because of its tendency to induce vomiting at high levels, will pass through the brewing process into the beer. When the beer is opened the toxin will cause the liquid to overflow from the bottle or can. Therefore because this is not commercially appealing barley producers receive severe price discounts when vomitoxin is present ^[44].

Currently control of barley scab is seen as a high priority resulting in the U.S. National Wheat and Barley Scab Initiative. In 2005 alone North Dakota State experts estimated that scab cost the North Dakota farm economy $162 million and in 1993 it cost North Dakota, South Dakota, and Minnesota $1 Billion. Fungicide trials in 2004 were promising. Results demonstrated that fungicide use reduced scab from 77-85%, reduced vomitoxin levels from 49-69%, and increased yields from 10-14%.

Stripe Rust

Stripe rust is a recent fungus to arrive in North and South America. The disease was first observed in Colombia in 1975 and it is believed it was brought over from Europe ^[44]. In the U.S. it was first discovered in Texas in 1991 and by the mid-90s it could be found throughout barley crops in the western states. Stripe rust is now established in California, Idaho, Oregon, and Washington and all other barley areas of the Pacific Northwest are considered highly susceptible ^[45]. Between 1996 and 1998 alone in Oregon yield losses of 25-50% were reported and in California between 15 and 30% were recorded ^[46] ^[47]. The state of Idaho estimates that without fungicide use yield losses would be 40% as opposed to 5% with fungicide application ^[45]

Blueberries

Blueberries are susceptible to a number of fungal diseases. These have been shown by the USDA to reduce yields by 25-60% if left uncontrolled ^[15].

Alternaria Leaf Spot

Leaf spot was first identified in North Carolina in the early 1970s when it was found to be causing a widespread fruit decay in blueberries ^[48] ^[49]. The disease is especially harmful to growers because symptoms of the disease do not develop until May, about a month before the June harvest. When the fruit ripens it becomes covered in a greenish fungal growth and can become leaky ^[49]. Since the fungus develops late in the harvest it has been found that fungicides applied at early bloom and every two weeks following until harvest are an effective control ^[49].

Botrytis Blight

Botrytis blight is a grey mold fungus that was first observed on New Jersey blueberries in 1924 and by the 1950s was considered the most dangerous disease of the Northwest ^[49]. USDA estimates that 95% of Northwestern blueberry crop and 40% of eastern blueberry fields are infected with botrytis blight. Yield losses within these fields with uncontrolled blight is estimated to be between 30-40% ^[11]^[15]. In most cases infections in the blossoms of the plant results in ovary mortality which prevents development of the blueberry itself ^[49].

Fusicoccum Canker

Fusicoccum canker is a disease of the blueberry that is mostly limited to Michigan blueberry producers. It was first discovered in the 1960s and has been a annual problem of the lower portion of the peninsula ^[50] ^[51]. When left uncontrolled the disease has been shown to reduce yields by 30% ^[15]. Captan is primarily used to control fusicoccum canker. Research has shown that regular applications can reduce infectious cankers by 82-95% ^[51]^[49]

Mummyberry

This fungal infection strikes the blueberry plant in the early spring. Over the winter the mummyberry infection incubates in the mummified blueberry fruit that has fallen on the ground and in the spring cup-shaped structures of the fungus begin to grow. These structures will then eject spores for nine days at an average of sixty thousand spores per day ^[52]. These spores are carried by the wind to the twigs and flowers of developing blueberry plants. No symptoms are visible however until right before harvest when the blueberries turn an orange or white color and then dry up ^[53]. These berries then fall to the ground where they serve as the hosts for the next year’s mummberry infection. If the infection is left uncontrolled the USDA estimates that blueberry yields would fall an average of 20 to 50% ^[11]^[15]. The state of Maine estimated their yields would drop 25% and Michigan has reported that they would lose 25-57% of the crop if left uncontrolled ^[54] ^[55]. Experiments with fungicide applications have reduced the incidence of mummyberry at harvest from 21-24% to 0.4% and increased yield up to 34% ^[56] ^[57] ^[58].

Phytophthora Root Rot

Phytophthora root rot was first reported in the blueberry plant in 1963. In plants surveyed in North Carolina it was found that 40% of plants were infected with the disease ^[49]. Symptoms of root rot include yellowing or reddening of leaves, heavy defoliation, and stunted plant growth ^[59]. Today current USDA estimates are that 80% of eastern blueberry acres are infected with root rot and it has the potential to reduce yields up to 25% ^[15].

Pseudomonas Blight

Pseudomonas blight is a bacterial disease that invades the blueberry plant early in the season when tissue is damaged from freezing temperatures. The bacteria invade the tissue of the plant and spread throughout the plant as long as it remains cool and damp. As the infection spreads thin strands of ooze will appear on the surface of the tissue. ^[60]. When temperatures rise the disease will retreat until fall when the colder weather allows it to return. Copper is primarily used to control the bacteria population.

Ripe Rot

Ripe rot, the more common name for anthracnose, is a disease localized mostly to the northern and southern blueberry-growing regions. However is has been spreading east and it is now estimated to infect 30% of the eastern blueberry growing regions ^[15]. Much like leaf spot ripe rot symptoms appear as the blueberry begins to ripen and mature ^[49]. Once the blueberry has ripened, it will soften and orange spores will be exuded. This disease can be especially costly because if a diseased berry showing no symptoms is put in a container of untainted berries it can very quickly infect the entire container. Control of this disease is achieved with fungicidal applications every 1-2 weeks ^[49].

Septoria Leaf Spot

Septoria leaf spot infects the blueberry plant through spores ejected from infected leaves and stem lesions left on the ground from the previous harvest season. These spores infect the crop and small white/tan leaf lesions form on the plant and the stem in early May. These lesions continue to develop and multiply through September ^[61]. Severe infection will cause defoliation of the plant. This will lower fruit yield as the nutrient supply is reduced. In weaker infections where defoliation does not occur the loss of photosynthetic area to due of the leaf will reduce yields as well ^[61]. Use of fenbuconazole has been shown to be successful in controlling leaf spot. If applied at harvest it will help prevent leaf spot from forming the next year. It has been shown to average 45% greater yields in the next harvest ^[62].

Cabbage

Alternaria Leaf Spot

Alternaria leaf spot affects the cabbage plant by causing severe spotting and discoloration to the head of the plant. It is only a superficial effect to the plant but because of the black color of the leaf spots the marketability of a severely infected cabbage crop is low ^[63]. Without control leaf spot is estimated to be able to reduce yields by up to 50% ^[64]. In order to control alternaria leaf spot the same treatment as downy mildew is used, applications of azoxystrobin, copper, chlorothalonil, mancozeb, and maneb beginning midseason.

Black Rot

Due to its ability to spread rapidly and destroy entire fields of crops black rot can be considered the most serious disease of the cabbage plant. Under the right conditions one plant has the ability to spread the disease to an entire field and cause 100% yield loss ^[64]. The disease thrives in areas with heavy rainfall and warmer temperatures ^[63]. The bacteria invade the plant through the water the plant absorbs and once inside spreads rapidly. It obtains its name because it will blacken and clog the veins of the plant making it impossible to keep nutrients moving through the plant ^[65]. Copper is the primary treatment for black rot control.

Clubroot

Clubroot gets its name from its primary symptom, enlargement of the plant roots. The abnormally large roots are unable to properly absorb water and nutrients from the ground and the result is cabbages that are undersized, wilted, and discolored ^[63]. If left uncontrolled yield losses due to clubroot can be as high as 50% ^[65]. The only fungicide shown to be effective in treating clubroot is PCNB ^[63]

Downy Mildew

Downy mildew when left uncontrolled has shown the ability to reduce yields up to 55% and infest up to 80% of plants ^[64]. Downy mildew is primarily controlled through the use of several fungicides applied during midseason. The fungicides used include azoxystrobin, copper, chlorothalonil, mancozeb, and maneb. Farmers in Florida who regularly use fungicides have been shown to reduce yield losses due to downy mildew to as low as 2% ^[66]

Carrots

Bacterial Blight

Bacterial blight if left uncontrolled has been shown to cause yield losses up to 20% ^[67]. The symptoms of the disease include small, dry, and brittle yellowish-brown spots on the plant and stalks covered in bacterial ooze ^[68]. The primary treatment of bacterial blight is applications of copper before the crop is fully mature ^[68].

Cavity Spot

Cavity spot differs from the other diseases of the carrot in that symptoms are only visible on the roots of the plant and therefore it is impossible to tell if a plant is infected from above ground. The primary symptom of cavity spot is small half-inch lesions on the roots of the plant. This disease is treated with metalaxyl which allows for almost complete control of the disease. Without metalaxyl studies have found 50-60% of the carrot crop will be infected, however, after metalaxyl application, incidence is under 1% ^[69]

Powdery Mildew

Powdery mildew is one of the more recent diseases of carrots. It was first discovered in 1975 in the United States in the warmer climates of California and Texas. Powdery mildew will cover the carrot with a film of white fungal growth which although does not kill the plant, it will stunt the growth of the carrot ^[70] ^[71]. These weaker plants therefore make it nearly impossible to harvest the carrots mechanically.

Collards

There are three major disease of collards, Alternaria, downy mildew, and black rot. Alternaria symptoms are small brown lesions on the surface of the collard leaf. Downy mildew produces small yellow fungal spots on the leaf that will cause the plant to wither and die. Finally, black rot gets its name because its primary symptom is the fungus will infect the veins of the plant and turn them black. These black veins will eventually collapse and the plant will die ^[72]. All three of these diseases are controlled with copper sprays.

Cotton

Pythium and Rhizoctonia

Pythium and rhizoctonia are both seedling diseases of the cotton plant. They can be the devastating to cotton plants because they develop when seedlings are unable to overcome the damage being caused by the invading fungus. The disease will often kill the seed before it grows. However if the seeds do manage to sprout they will demonstrate symptoms almost immediately. The stalks of the cotton plant will be weak, brown sunken lesions will appear on the stem, and the plant will often die before producing or will have very poor yields ^[73]. Growers who plant early are especially susceptible because the early plant means cooler temperatures and damper weather which is conducive to these diseases. Therefore growers who plant early are advised to use in-furrow fungicides (PNCB and iprodione on Rhizoctonia and etridiazole and mefnoxam on pythium) for control ^[74]. Recently, azoxystrobin has proven effective in controlling both rhizoctonia and pythium.

Rust

Rust primarily attacks plants in Arizona, New Mexico, and Texas ^[75]. The disease attacks during the summer months and causes yellow or orange spots to grow on the leaves of the cotton plant. These spots can cause defoliation, premature openings, broken stems, and reduced yield ^[76]. Crops with severe outbreaks have been known to incur losses of up to 50% ^[75]. This disease is controlled with applications of mancozeb.

Garlic

Rust

Early symptoms of garlic rust are small yellow spots on the leaves of the plant that soon expand until the leaf tissue shatters and visible pustules emerge. Diseased bulbs will lose their protective dry outer skin which not only means the garlic loses its ability to photosynthesize; the garlic is prone to shatter when mechanically harvested. In trials tebconazole and azoxystrobin have been shown to provide 50% higher yields in treated crops ^[77].

Grapes

Black Rot

Black rot is a disease estimated to affect 95% of all eastern grape vineyards. The USDA estimates it could reduce yields by 85% if left untreated ^[15]. Black rot is spread through spores left in the mummied grapes infected the year before. Upon infection the grapes will shrivel up and turn black ^[78]. These grapes will not fall from the vine but instead will stay attached and over the winter spores grow within the infected grape. When summer comes the rain will re-moisten the dried up grape and cause it to swell. Spores will discharge from the swollen grape into the air and infect the healthy crop ^[79]. Prior to fungicide development for black rot in favorable conditions losses of 70 to 100 percent of the crop were common ^[79]. Today however applications of fungicides have been able to give almost complete control of the disease. In many vineyards infections can be reduced from 95% down to 1% ^[80].

Botrytis Bunch Rot

Cold and wet climates favor this disease, which is why it is often found in the coastal vineyards of California and New York ^[81]. In the eastern vineyards this disease is estimated to infect 30% of grapes while in California it can infect up to half ^[82]. This can reduce yields by 40-60% ^[15] ^[83]. Much like black rot, bunch rot overwinters in the berries and will infect the next season’s crop through spore ejections in the summer ^[84]. Originally Bordeaux mixturewas used to controlled botrytis bunch rot but the use of synthetic chemicals is now the preferred method ^[85].

Phomopsis Cane and leaf spot

Cane and leaf spot is a disease found rarely in California but on large areas of the East coast. The USDA estimates it affects 75% of the acres of eastern vineyards with the potential to reduce yields up to 15% ^[15]. The disease can result in lesions, defoliation, and berry rot. However the same fungicide sprays used to control black rot done early in the season have been shown to control cane and leaf spot.

Powdery Mildew

Powdery mildew was first reported in European grape vineyards in the mid 1850’s. It could reduce yields by up to 80%. In France alone it reduced wine production from a billion gallons to only two hundred million gallons ^[86]. It was as a result of this disease’s rapid spread throughout the continent that the first fungicide, sulfur, was discovered ^[87]. The success of sulfur was so great that the grape industry was sparked in California when it was seen that disease could now be controlled and grapes now easy to grow. Powdery mildew if uncontrolled will rot the grapes from the inside out. Powdery mildew slows the growth of the grape skin so that the inside pulp grows at a faster rate and bursts through. These split grapes then dry up and rot ^[88]. For the grapes that manage to not split open they are of a much lower quality than normal grapes. Their acidity is much higher and as a result the wines will taste bitter and off flavor to most wine drinkers ^[89]. In order to control powdery mildew the same treatment that was recommended in the late 1800’s is still used today: regular applications of sulfur every 1-2 weeks ^[90].

Green Beans

Alternaria

Alternaria was first reported on green beans in Florida in 1951 after a hundred acres were lost to the disease in one season ^[91]. By the 1970s it had spread up the coast to New York ^[92]. The disease causes lesions on the skin of the green bean to grow, killing the tissue and giving the plant a moldy appearance ^[93]. However trials have shown that applications of chlorothalonil can reduce alternaria by up to 85% ^[92]

Bacterial Blight

Bacterial blight is endemic to green bean crops grown east of the Rocky Mountains ^[63]. During ideal conditions (usually humid weather) the disease can inflict losses as high as 60% ^[94]. Symptoms include lesions resemble burn marks that gradually grow larger ^[93]. In some states incidence of the disease can be as high as 100% ^[95]. Trials have shown that properly timed copper sprays can reduce incidence by 90% ^[96].

Root Rot

Root rot is a common disease of Florida green beans and can reduce crop yields there by up to 75% if untreated ^[95]. It was not until the 1950s that an effective fungicide was found to control root rot. Trials in Florida in the 1950s showed that applications of PCNB were able to reduce incidence down to 3% ^[97]. PCNB is still the primary treatment today ^[98].

Powdery Mildew

Powdery mildew appears on the green bean plant as a white mold on the surface of the green bean leaf. This grows and can cover the entire plant with this powdery fungal growth ^[93]. Yield losses occur because the damage makes the crop not commercially viable ^[63]. However powdery mildew can be controlled with applications of sulfur. The original trials in the 1930s showed that incidence could be reduced from 87% to 2% ^[99].

Rust

Bean rust is a disease of the green bean that causes rust-color pustules on the leaves of the plant. These pustules eventually rupture and eject thousands of spores into the air to be carried to other plants ^[63]. Each individual spore can produce a fresh pustule on a plant within a week; therefore rust can rapidly reach epidemic levels if left untreated ^[63]. When leaves become infected with rust they will rapidly die causing defoliation. However research in the 1930s discovered that sulfur was an effective treatment for rust and since then yield losses due to rust is now reduced by 60% in treated fields ^[100].

White Mold

Before effective fungicides were developed white mold caused significant hardship for green bean growers. White mold is considered a resilient disease. After infecting the plant the white mold will produce black formations called sclerotia that fall to the soil and can survive in the soil for over five years until the conditions are right for infection again ^[101]. Since white mold affects plants very late in the growing season farmers would often harvest early in order to avoid losing much of their crop. However this usually resulted in a 30% loss of crop. Research in the 1970s eventually discovered that fungicides applied every 20 days reduced white mold incidence to 0% in treated areas ^[102]

Hazelnuts

Eastern filbert blight

Eastern filbert blight or EFB was first introduced to U.S. hazelnut orchards through imported European hazelnut trees in the 1920s. By the 1970s this disease had spread all the way from its New York origins to the west coast. In hazelnuts the EFB will cause cankers to form on the tree and will slowly expand and kill the tree over the course of several years if diseased tree limbs are not removed in time ^[103]. Research with chlorothalonoil and tebuconozole in the 1990s showed that 4-5 applications of the fungicides on a 2 week schedule when vegetative buds are breaking dormancy is ideal for control of EFB ^[104]. The state of Oregon has estimated that if left uncontrolled EFB could eliminate half of the state’s hazelnuts within ten years ^[105].

Hot peppers

New Mexico accounts for the vast majority of U.S. hot pepper production. It is the number one producing state and accounts for roughly 65% of all U.S. hot pepper production.

Bacterial Spot

Bacterial spot is spread from plant to plant through water, wind, and plant contact. Once infected, the leaves of the plant are targeted by the disease. The disease causes severe spotting of the pepper and kills the leaves of the plant ^[106]. This is a twofold problem because the defoliation of the plant will result in the pepper being discolored by sunscald. Research for bacterial spot treatment has shown that copper sprays have been able to increase marketable yields by 50% in treated fields ^[107].

Powdery Mildew

Powdery mildew causes a white powdery growth to cover the leaves of the hot pepper plant. These leaves may drop prematurely and as with bacterial spot can then cause sunscald ^[108]. This disease has been known to cause yield losses as high as 50-60% in untreated fields ^[109]. The prime fungicide used to control powdery mildew is myclobotinil.

Lettuce

Bottom Rot

Bottom rot symptoms consist largely of deep reddish colored lesions on the leaves that slowly spread from leaf to leaf until the entire head is rotted ^[63]. Trials with vinclozolin have demonstrated effectiveness in controlling bottom rot. Research indicated that when treated, crop yields will rise about 36% ^[110].

Downy Mildew

Downy mildew is an extremely common disease of the lettuce plant. This is largely due to the diseases’ quick germination period, three hours, and the lettuce plant being susceptible at all growth stages. One study estimated that in untreated Florida fields 75% of lettuce was infected with downy mildew and considered unsalable ^[111]. Research with maneb has shown the ability to reduce the number of lesions per 10 plants from 187 to about one ^[112]. EBDC and fosetyl-al have also been shown effective in Florida trials that reduced unmarketable heads to 2% after fungicidal treatments ^[111].

Lettuce Drop

Lettuce drop is another resilient disease of the lettuce plant. It can be found in all lettuce growing regions of the U.S. and is able to survive in the soil for up to a decade once the disease infects a field ^[113]. The fungus appears on the plant as a white mass on the leaf that slowly turns into a hard black growth. These growths release spores that infect the lettuce plant with pathogens that slowly move up the stalk of the plant killing tissue as it travels ^[63] ^[113]. Use of DCNA, iprodione, and vinclozolin about a month before harvest has been shown to significantly reduce lettuce drop in treated fields ^[113]. In treated California fields fungicides are able to reduce yield losses as low as 5% ^[114].

Powdery Mildew

Powdery mildew attacks lettuce plants by robbing them of the nutrients within the leaf. The fungus appears as a white growth on the upper surface of the leaf where it will uses small tubes to pull nutrients out of the plant ^[63]. This causes severe discoloration and eventual defoliation of the plant. Applications of sulfur are recommended as the primary way to control powdery mildew on lettuce ^[113].

Onions

Downy Mildew

Downy mildew is an extremely fast developing disease in the onion. Studies have observed up to 40% of a field being infected in less than three days ^[115]. The first symptoms of the disease are white and purple growths on the surface of the plant leaves. Eventually these leaves die. This in turn destroys the plant’s photosynthetic abilities and stunts the growth and sometimes kill the plant ^[116]. If left unchecked downy mildew has the capability of reducing yields by 65% ^[117]. Downy mildew is controlled with the same foliar fungicides as leaf blight: azoxystrobin, copper, mancozeb, maneb, and mefenoxam.

Botrytis Leaf Blight

Leaf blight occurs in areas with hot and humid weather. The leaf blight spores land on onion leaves, penetrate the skin, and rapidly kill the leaf. This causes a severe reduction in bulb size, as high as 50%, and can happen in less than a week ^[118]. Applications of foliar fungicides can be used to control leaf blight. These include: azoxystrobin, chlorotholonil copper, mancozeb, maneb, and mefenoxam.

Purple blotch

Symptoms of purple blotch are primarily small white lesions that grow larger as they turn purple and brown. From these lesions spores are produced that cause additional lesions and also spread to other plants. However to develop, the disease requires very wet conditions for an extended period of time ^[117]. Fungicide treated fields have been found to have yields roughly 20-35% higher as opposed to untreated fields ^[119]

Seed rot

Yield loss due to seed rot can be as high as 30% in heavily infected acres ^[120]. The disease infects the onion seed and will cause the onions roots to be gray and mushy. These roots and plants will rapidly decay and decompose, killing the plant ^[121]. Mefenoxam is recommended as treatment for seed rot.

Smut

Smut is a tough disease of the onion because it can last for years in the soil as spores. When the onion crop is planted the spores will germinate and enter the fresh seeds ^[120]. When the plant grows lesions will form on the leaf and any bulbs that form will be covered in black spots. Most of the time infected seeds will die within 3-5 weeks of planting ^[120]. Mancozeb is recommended for treatment of smut.

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^ Crossan, DF (April 15, 1963). "A Comparison of Fixed Copper and Dodine sprays with Various Additives for control of Bacterial Spot of Pepper Fruit". Plant Disease Reporter. 47 (4): 239. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
^ Pernezny, Ken (2003). Compendium of Pepper Diseases. APS Press. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
^ Smith, Richard f. (November-december 1999). "Several Fungicides Control Powdery Mildew in Peppers". California Agriculture. 53 (6): 40. {{cite journal}}: Check date values in: |date= (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)
^ Riedel, R.M. (1990). "Chemical and Biological Control of Bottom Rot of Lettuce". Fungicide and Nematicide Tests. 45: 113. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
^ ^a ^b Raid, R.N. (1989). "Efficacy of Fosetyl-AL Foliar Application in Controlling Downy Mildew of Lettuce". Proceedings of the Florida State Horticultural Society. 102: 362. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
^ Greathead, Arthur S., et al, “Fungicidal Control of Downy Mildew and Anthracnose of Lettuce,” Iceberg Lettuce Research Program, 6th Annual Report, University of California, 1980
^ ^a ^b ^c ^d Davis, Michael R. (1997). Compendium of Lettuce Diseases. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
^ "Pest Management Strategic Plan for California and Arizona Lettuce Production" (PDF). USDA. February 2003.
^ Onion Downy Mildew, University of California Cooperative Extension Service, March, 1995
^ Yarwood, C.E. (February 1943). "Onion Downy Mildew". Hilgardia. 14 (11). {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
^ ^a ^b "Crop Profile for Onion in Texas". USDA. June 2003.
^ McLean, D.M (1959). "Tip and Leaf Blight of Onions in the Lower Rio Grande Valley". Journal of the Rio Grande Valley Horticultural Society. 13. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
^ "Crop Profile for Onions in Wisconsin". USDA. January 1999.
^ ^a ^b ^c "Crop Profile for Onions in New York". USDA. May 1999.
^ Schwartz, Howard F. (1995). Compendium of Onion and Garlic Diseases. APS Press. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[one-1] Teviotdale, B.L. (May 2001). "First Report of Alternaria Leaf Spot of Almond Caused by Species in the Alternaria alternata Complex in California". Plant Disease. 85 (5). {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[two-2] Specific Section 18 Emergency Exemption Request to use Azoxystrobin (Abound Flowable) to Control Alternaria on Almonds in San Joaquin Valley of California, California Department of Pesticide Regulation, 1999.

[three-3] Teviotdale, Beth L., et al., eds., Compendium of Nut Crop Diseases in Temperate Zones, APS Press, 2002

[four-4] Anthracnose called ‘Ugliest Orchard Disease’ by Farm Advisor, Ag Alert, August, 14, 1996

[five-5] Specific Exemption for Use of Propiconazole (Break EC) for Control of Anthracnose on Almonds in California, California Department of Pesticide Regulation, Section 18 Emergency Exemption Request, November, 1997.

[six-6] ^ ^a ^b ^c ^d ^e ^f ^g ^h "Crop Profile for Almonds in California". USDA. January 1999. Retrieved 2009-05-07.

[seven-7] "Blossoms: Radioactive Fungicides on Trail of Almond Brown Rot". Ag Alert. February 14, 1990. {{cite news}}: |access-date= requires |url= (help); Cite has empty unknown parameter: |1= (help)

[eight-8] Integrated Pest Management for Almonds, University of California, Statewide Integrated Pest Management Project, Publication 3308, 1985.

[nine-9] ^ ^a ^b ^c ^d ^e ^f ^g Years of Discovery: A Compendium of Research Projects 1972-1998, Almond Board of California, 1999.

[ten-10] Ogawa, Joseph (February 1959). "The Leaf Blight Disease of Almond and its Control". Hilgardia. 28 (10). {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[eleven-11] ^ ^a ^b ^c ^d ^e ^f ^g Gubler, W. Douglas, Fungicide Benefits Assessment Fruit and Nut Crops - West, USDA National Agricultural Pesticide Impact Assessment Program, January, 1991.

[twelve-12] Teviotdale, Beth (May–June 1989). "Effect of Fungicides on Shot Hole Disease of Almonds". California Agriculture. 43 (3). {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)CS1 maint: date format (link)

[thirteen-13] Keitt, G.W., “Scab of Apples,” Yearbook of Agriculture 1953, United States Department of Agriculture, p. 646, 1954.

[fourteen-14] ^ ^a ^b ^c ^d ^e ^f ^g ^h Jones A.L., and H.S. Aldwinckle, eds., Compendium of Apple and Pear Diseases, APS Press, 1990.

[fifteen-15] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m Hickey, Kenneth D., Fungicide Benefits Assessment Fruit and Nut Crops - East, USDA National Agricultural Pesticide Impact Assessment Program, January, 1991.

[sixteen-16] Yoder, K.S. (December 1981). "Sterol-Inhibiting Fungicides for Control of Certain Diseases of Apple in the Cumberland-Shenandoah Region". Plant Disease. 65 (12): 998. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[seventeen-17] Latham, A.J. (October 1983). "Cultural Characteristics and Pathogenicity of Glomerella cingulata Isolates from Apples in Alabama". Plant Disease. 67 (10): 1065. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[eighteen-18] Hurt, R.H., and F.J. Schneiderhan, New Methods of Bitter Rot Control, Virginia Agricultural Experiment Station, Bulletin No. 254, February, 1927.

[nineteen-19] Dunegan, John C., “Bitter Rot of Apples,” Yearbook of Agriculture 1953, United States Department of Agriculture, p. 655, 1954.

[twenty-20] Palmiter, D.H. (October, 1951). "A Blossom End Rot Outbreak in Hudson Valley Orchards". Farm Research: 15. {{cite journal}}: Check date values in: |date= (help)

[twentyone-21] Yoder, K.S. (1986). "Fungicide Control of Brooks Fruit Spot of Apple". Plant Disease. 66: 564.

[twentytwo-22] Steward, P. (May 5, 2000). "Washington Growers Monitor Orchards for Fire Blight". Capitol Press.

[twentythree-23] Moller, W.J. (July, 1981). "The Scenario of Fire Blight and Streptomycin Resistance". Plant Disease. 65 (7): 563. {{cite journal}}: Check date values in: |date= (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)

[twentyfour-24] Yoder, K.S. (February 1983). "Control of Apple Powdery Mildew in the Mid-Atlantic Region". Plant Disease. 67 (2): 245. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[twentyfive-25] Palmiter, D.H., Rust Diseases of Apples and Their Control in the Hudson Valley, New York State Agricultural Experiment Station, Bulletin No. 756, November, 1952.

[twentysix-26] Sutton, T.B. (1981). "Production and Dispersal of Ascospores and Conidia by Physalospora obtusa and Botryosphaeria dothidea in Apple Orchards". Phytopathology. 71 (6): 584.

[twentyseven-27] Specific Exemption for Use of Myclobutanil for Control of Powdery Mildew on Artichoke in California, California Environmental Protection Agency, Section 18 Emergency Exemption Request, May 27, 1998.

[twentyeight-28] "Artichoke Powdery Mildew". UC Pest Management Guidelines. 01/02. Retrieved 2009-05-18. {{cite web}}: Check date values in: |date= (help)

[twentynine-29] Falloon, Peter, G. (November 1985). "Control of Phytophthora rot with Metalaxyl in Established Asparagus". Plant Disease. 69 (11): 921–923. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)CS1 maint: multiple names: authors list (link)

[thirty-30] Falloon, Peter G. (January 1986). "Effect of phytophthora megasperma var. sojae on Yield of Asparagus officinalis". Plant Disease. 70 (1): 15–19. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[thirtyone-31] Elmer, Wade H (May 2001). "Economically Important Diseases of Asparagus in the United States". Plant Health Progress.

[thirtytwo-32] Meyer, M.P. (May 2000). "Optimal Fungicide Management of Purple Spot of Asparagus and Impact on Yield". Plant Disease. 84 (5): 525–530. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[thirtythree-33] Hausbeck, Mary (May 1999). "Controlling Purple Spot on Asparagus is an Investment in Future Yield". The Vegetable Growers News. p. 33. {{cite news}}: |access-date= requires |url= (help)

[thirtyfour-34] Halsted, Byron D., The Asparagus Rust; Its Treatment and Natural Enemies, New Jersey Agricultural Experiment Station Bulletin 129, 1898.

[thirtyfive-35] Smith, Ralph E., Further Experience in Asparagus Rust Control, University of California, College of Agriculture, Agricultural Experiment Station Bulletin 172, 1906.

[thirtysix-36] Kahn, Robert P., et al., An Investigation of Asparagus Rust in Illinois; Its Causal Agent and Its Control, University of Illinois, Agricultural Experiment Station Bulletin 559, 1952

[thirtyseven-37] Linn, M.B. (May 15, 1958). "Zineb as a Protective Fungicide for the Control of Asparagus Rust". Plant Disease Reporter. 42 (5): 669–672. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[thirtyeight-38] Hausbeck, M.K. "Control of Disease of Asparagus with Foliar Sprays, 1991". Fungicide and Nematicide Tests. 47: 75. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[thirtynine-39] "Pest Management Strategic Plant for Banana Production in Hawaii" (PDF). USDA. March 2003. Retrieved March 2003. {{cite web}}: Check date values in: |accessdate= (help)

[forty-40] Ploetz, R.C. et al., ed., Compendium of Tropical Fruit Diseases, APS Press, 1998

[fortyone-41] Marin, Douglas H. (March 2003). "Black Sigatoka: An Increasing Threat to Banana Cultivation". Plant Disease. 87 (3): 208–222. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[fortytwo-42] Trujillo, E.E. (1964). "The Distribution of Sigatoka Disease of Bananas in Hawaii". Hawaii Farm Science. 13: 10–12. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[fortythree-43] McMullen, Marcia (December 1997). "Scab of Wheat and Barley: a Re-emerging Disease of Devastating Impact". Plant Disease. 81 (12): 1340. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[fortyfour-44] Mathre, D.E., ed., Compendium of Barley Diseases, 2nd Edition, APS Press, 1997

[fortyfive-45] Specific Exemption for Use of Tebuconazole (Folicur 3.6F) for Control of Stripe Rust infesting Barley in Idaho, Oregon, and Washington, Idaho Department of Agriculture, Section 18 Emergency Exemption Request, January 16, 1998.

[fortysix-46] “Barley Growers fighting Strip Rust,” Capital Press, July 18, 1997

[fortyseven-47] “Heat, Strip Rust Damage Nw, California Barley Crop,” Capital Press, September 18, 1998

[fortyeight-48] Milholland, R.D. (1973). "A Leaf Spot disease of Highbush Blueberry caused by Alternaria Tenuissima". Phytopathology. 63: 1395–1397.

[fortynine-49] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Caruso, Frank L. (1995). Compendium of Blueberry and Cranberry Diseases. APS Press. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[fifty-50] Weingartner, D.P. (February 1975). "Etiology and Symptomatology of Canker and dieback Disease on Highbush Blueberries caused by Godronia (Fusicoccum) cassandrae and Disaporthe (phomopsis) vaccinii". Phyopathology. 65: 105–110. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[fiftyone-51] Parker, P.E. (1997). "Epidemiology and Chemical Control of Godronia Canker of Highbush Blueberry". Phytopathology. 67: 1475–1480. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[fiftytwo-52] Lehman, Jeffrey S. (2000). "Variation and Heritability of Phenology in the fungus Monilinia vaccinii-corymbosi on Blueberry". Phytopathology. 30: 390–395. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[fiftythree-53] Stretch, A.W. (June 1995). "Mummyberry Disease Blight Resistance in Highbush Blueberry Cultivars". HortScience. 30: 589. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[fiftyfour-54] Section 18, Specific Exemption, Petition for use of Propiconazole, Orbit Fungicide, EPA Reg. No. 100-702, on wild blueberry fields in Maine to control Mummy berry disease, Maine Department of Agriculture, Food, and Rural Resources, Section 18 Emergency Exemption Request, December 17, 1997.

[fiftyfive-55] Section 18, Specific Exemption, Petition for use of Fenbuconazole, Indar Fungicide, to control mummy berry disease of blueberries in Michigan in 1999, Michigan Department of Agriculture, Section 18 Emergency Exemption Request, January 28, 1999

[fiftysix-56] Ramsdell, D.C. (November 1975). "Aerial Applications of Systemic and Nonsystemic Fungicides for Control of Mummyberry Disease of Highbush Blueberries". Plant Disease Reporter. 59 (11): 873. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[fiftyseven-57] Lambert, D.H. (1988). "Evaluation of Fungicides for Control of Botrytis Blight on Lowbush Blueberry". Fungicide and Nematicide Tests. 43. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[fiftyeight-58] Bristow, P.R. (1996). "Field Evaluation of Fungicides for Control of the Mummyberry disease, 1995". Fungicide and Nematicide Tests. 51. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[fiftynine-59] Royle, D.J. (April 15, 1963). "Phytophthora Cinnamomi on highbush Blueberry". Plant Disease Reporter. 47 (4): 266. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[sixty-60] Ellis, Michael A. (1991). Compendium of Raspberry and Blackberry Disease and Insects. APS Press. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[sixtyone-61] Roloff, I. (April 2004). "Photosynthesis of Blueberry Leaves as Affected by Septoria Leaf Spot and Abiotic Leaf Damage". Plant Disease. 88 (4): 397–401. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[sixtytwo-62] Cline, W.O., “Blueberry Bud Set and Yield Following the Use of Fungicides for Leaf Spot Control in North Carolina,” Proceedings of the 7th International Symposium of Vaccinium, Acta Horticulturae, Vol. 574, 2002

[sixtythree-63] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k Sherf, Arden F. (1986). Vegetable Disease and Their Control. John Wiley & Sons. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[sixtyfour-64] "Crop Profile for Cabbage in Texas". USDA. May 2003.

[sixtyfive-65] "Crop Profile for Cabbage in New York". USDA. May 1999.

[sixtysix-66] "Crop Profile for Cabbage in Florida". USDA. June 2000.

[sixtyseven-67] "Crop Profile for Carrots in Texas". USDA. May 2003.

[sixtyeight-68] Davis, Michael R. (2002). Compendium of Umbelliferous Crop Diseases. APS Press. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[sixtynine-69] Farrar, James J. (March–April 2002). "Repeated Soil Applications of Fungicide Reduce Activity Against Cavity Spot in Carrots". California Agriculture. 56 (2): 76–79. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)CS1 maint: date format (link)

[seventy-70] Kontaxis, Demetrois G. (August 1976). "Powdery Mildew on Carrots-A New Disease". California Agriculture. 30: 15.

[seventyone-71] "Crop Profile for Carrots in Michigan". USDA. August 1999.

[seventytwo-72] "Crop Profile for Leafy Greens in Georgia". USDA. July 2001.

[seventythree-73] Minton, Earl B. (January 1983). "Controlling the Seedling Disease Complex of Cotton". Plant Disease. 67 (1): 115. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[seventyfour-74] "Applying a Fungicide May Prevent Cotton Replanting". Ag Alert. March 27 2002. {{cite news}}: Check date values in: |date= (help)

[seventyfive-75] Hine, Richard, and Jeffery C Silvertooth, Diseases and Production Problems of Cotton in Arizona, University of Arizona Cooperative Extension Service, No. 8927, March, 1990.

[seventysix-76] Kirkpatrick, T.L. (2001). Compendium of Cotton Disease. APS Press. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[seventyseven-77] Koike, Steven T. (September–December 2001). "Rust Disease Continues to Threaten California Garlic Crop". California Agriculture. 55 (5): 35–39. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)CS1 maint: date format (link)

[seventyeight-78] Pearson, R.C., Black Rot Grape IPM Disease Identification Sheet No. 4, New York State Agricultural Experiment Station, 1984.

[seventynine-79] Ferrin, Donald M. (1977). "Ascospore Dispersal and Infection of Grapes by Guignardia bidwellii, the casual Agent of Grape Black Rot Disease". Phytopathology. 67: 1501. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[eighty-80] Ellis, M.A. (October 1986). "Electronic Grape Black Rot Predictor for Scheduling Fungicides with Curative Activity". Plant Disease. 70 (10): 938. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[eightyone-81] Pearson, R.C. (1983). "Control of Botrytis Bunch Rot of Ripening Grapes: Timing Applications of the Dicarboximide Fungicides". American Journal of Enology and Viticulture. 34 (3): 167. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[eightytwo-82] McClellan, W.D. (1973). "Early Botrytis rot of Grapes and its Control". American Journal of Enology and Viticulture. 24 (1): 27. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[eightythree-83] "Botrytis is an Ever-Present Threat in Winegrapes". Ag Alert. May 10, 1995.

[eightyfour-84] Pearson, Roger c. (August 1979). "Botrytis Bunch Rot: Understanding The Disease, Strategies for Control". Eastern Grape Grower and Winery News. p. 18.

[eightyfive-85] Braun, Alvin J. (1949). "Some Effects of Fermate and Bordeaux sprays on Concorn Grapes". Phytopathology. 39: 3.

[eightysix-86] Carefoot, G.L. (1967). Famine on the Wind: Man's Battle Against Plant Disease. Rand McNally & Company. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[eightyseven-87] Spencer, D.M. (1978). The Powdery Mildews. New York: Academic Press.

[eightyeight-88] Pearson, Roger C. (1988). Compendium of Grape Diseases. APS Press. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[eightynine-89] Ough, C.S. (1979). "Research Note: Powdery Mildew Sensory Effect on Wine". American Journal of Enology and Viticulture. 10 (4): 321. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[ninety-90] Bioletti, Frederic T., Oidium or Powdery Mildew of the Vine, University of California, Agricultural Experiment Station, Bulletin No. 186, February, 1907

[ninetyone-91] Swank, George Jr. (July 15, 1951). "Alternaria Leaf Spot and Dieback of Snap Bean: A New Disease in Central Florida". Plant Disease Reporter. 35 (7): 330.

[ninetytwo-92] Abawi, G.S. (November 1977). "Pod-Flecking of Snap Beans Caused by Alternaria alternata". Plant Disease Reporter. 61 (1): 901. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[ninetythree-93] Hall, Robert (1991). Compendium of Bean Diseases. APS Press.

[ninetyfour-94] Delahunt, Karen A. (1997). "Processing Snap Bean Production: A Biologic and Economic Assessment of Pest Management and Pesticide Usage". University of Wisconsin. {{cite web}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[ninetyfive-95] "Crop Profile for Beans (Snap) in Florida". USDA. March 2003.

[ninetysix-96] Oshima, N. (July 1971). "Effects of Copper Sprays on Secondary Spread of Common Bacterial Blight of Beans". Plant Disease Reporter. 55 (7): 609. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[ninetyseven-97] Moore, W.D. (February 15 1955). "Chemical Soil Treatments for the Control of Rhizoctonia on Snap Beans". Plant Disease Reporter. 39 (2): 103. {{cite journal}}: Check date values in: |date= (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)

[ninetyeight-98] Crosson, D.F. (February 15 1963). "Control of Rhizoctonia root-Rot of Snapbean: Low Volume in-the-furrow Versus High Volume Preplant Fungicidal Sprays". Plant Disease Reporter. 47 (2): 109. {{cite journal}}: Check date values in: |date= (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)

[ninetynine-99] Moore, W.D. (1936). "Powdery Mildew (erysiphe polygoni) on Garden Snap Beans". Phytopathology. 26: 1135.

[hundred-100] McMillan Jr., R.T. (1982). "Fungicides for the Control of Squash Powdery Mildew and Bean Rust". Proceedings of the Florida State Horticultural Society. 95: 304–307. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[hundredone-101] Steadman, James R. (April 1983). "White Mold - A Serious Yield Limiting Disease of Bean". Plant Disease. 67 (4): 346.

[hundredtwo-102] Natti, J.J. (June 1971). "Epidemiology and Control of Bean White Mold". Phytopathology. 61 (6): 669.

[hundredthree-103] Johnson, Kenneth B. (December 1996). "Eastern Filbert Blight of European Hazelnut: It's Becoming a Managable Disease". Plant Disease. 80 (12): 1308–1316. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[hundredfour-104] Johnson, Kenneth B. (August 1993). "Evaluation of Chlorothalonoil, Fenarimol, and Flusilazole for Control of Eastern Filbert Blight". Plant Disease. 77 (8): 831–837. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[hundredfive-105] Specific Exemption for Use of Tebuconazole (Elite 45 DF Foliar Fungicide) for Control of Eastern Filbert Blight in Hazelnuts in Oregon, Oregon Department of Agriculture, Section 18 Emergency Exemption Request, December 20, 1999

[hundredsix-106] "Crop Profile for Peppers (Chile) in New Mexico". USDA. March 2000.

[hundredseven-107] Crossan, DF (April 15, 1963). "A Comparison of Fixed Copper and Dodine sprays with Various Additives for control of Bacterial Spot of Pepper Fruit". Plant Disease Reporter. 47 (4): 239. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[hundredeight-108] Pernezny, Ken (2003). Compendium of Pepper Diseases. APS Press. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[hundrednine-109] Smith, Richard f. (November-december 1999). "Several Fungicides Control Powdery Mildew in Peppers". California Agriculture. 53 (6): 40. {{cite journal}}: Check date values in: |date= (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)

[hundredten-110] Riedel, R.M. (1990). "Chemical and Biological Control of Bottom Rot of Lettuce". Fungicide and Nematicide Tests. 45: 113. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[hundredeleven-111] Raid, R.N. (1989). "Efficacy of Fosetyl-AL Foliar Application in Controlling Downy Mildew of Lettuce". Proceedings of the Florida State Horticultural Society. 102: 362. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[hundredtwelve-112] Greathead, Arthur S., et al, “Fungicidal Control of Downy Mildew and Anthracnose of Lettuce,” Iceberg Lettuce Research Program, 6th Annual Report, University of California, 1980

[hundredthirteen-113] Davis, Michael R. (1997). Compendium of Lettuce Diseases. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[hundredfourteen-114] "Pest Management Strategic Plan for California and Arizona Lettuce Production" (PDF). USDA. February 2003.

[hundredfifteen-115] Onion Downy Mildew, University of California Cooperative Extension Service, March, 1995

[hundredsixteen-116] Yarwood, C.E. (February 1943). "Onion Downy Mildew". Hilgardia. 14 (11). {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[hundredseventeen-117] "Crop Profile for Onion in Texas". USDA. June 2003.

[hundredeighteen-118] McLean, D.M (1959). "Tip and Leaf Blight of Onions in the Lower Rio Grande Valley". Journal of the Rio Grande Valley Horticultural Society. 13. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[hundrednineteen-119] "Crop Profile for Onions in Wisconsin". USDA. January 1999.

[hundredtwenty-120] "Crop Profile for Onions in New York". USDA. May 1999.

[hundredtwentyone-121] Schwartz, Howard F. (1995). Compendium of Onion and Garlic Diseases. APS Press. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

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@@ Line 161: / Line 161: @@
 ===Powdery Mildew===
 Powdery mildew is one of the more recent diseases of carrots. It was first discovered in 1975 in the United States in the warmer climates of California and Texas. Powdery mildew will cover the carrot with a film of white fungal growth which although does not kill the plant, it will stunt the growth of the carrot <ref name="seventy">{{cite journal|last=Kontaxis|first=Demetrois G.|date=August 1976|title=Powdery Mildew on Carrots-A New Disease|journal=California Agriculture|volume=30|pages=15}}</ref> <ref name="seventyone">{{cite web|url=http://pestdata.ncsu.edu/cropprofiles/docs/micarrots.html|title=Crop Profile for Carrots in Michigan|date=August 1999|publisher=USDA}}</ref>. These weaker plants therefore make it nearly impossible to harvest the carrots mechanically.
+==Collards==
+There are three major disease of [[collards]], Alternaria, downy mildew, and black rot. Alternaria symptoms are small brown lesions on the surface of the collard leaf. Downy mildew produces small yellow fungal spots on the leaf that will cause the plant to wither and die. Finally, black rot gets its name because its primary symptom is the fungus will infect the veins of the plant and turn them black. These black veins will eventually collapse and the plant will die <ref name="seventytwo">{{cite web|url=http://pestdata.ncsu.edu/cropprofiles/docs/GAleafgreen.html|title=Crop Profile for Leafy Greens in Georgia|date=July 2001|publisher=USDA}}</ref>. All three of these diseases are controlled with copper sprays.
 ==Cotton==
@@ Line 169: / Line 173: @@
 ===Rust===
 Rust primarily attacks plants in [[Arizona]], [[New Mexico]], and Texas <ref name=seventyfive> Hine, Richard, and Jeffery C Silvertooth, Diseases and Production Problems of Cotton in Arizona, University of Arizona Cooperative Extension Service, No. 8927, March, 1990.</ref>. The disease attacks during the summer months and causes yellow or orange spots to grow on the leaves of the cotton plant. These spots can cause defoliation, premature openings, broken stems, and reduced yield <ref name="seventysix">{{cite book|last=Kirkpatrick|first=T.L.|coauthors=C.S. Rothrock|title=Compendium of Cotton Disease|publisher=APS Press|date=2001}}</ref>. Crops with severe outbreaks have been known to incur losses of up to 50% <ref name=seventyfive/>. This disease is controlled with applications of mancozeb.
+==Garlic==
+===Rust===
+Early symptoms of [[garlic]] rust are small yellow spots on the leaves of the plant that soon expand until the leaf tissue shatters and visible pustules emerge. Diseased bulbs will lose their protective dry outer skin which not only means the garlic loses its ability to photosynthesize; the garlic is prone to shatter when mechanically harvested. In trials tebconazole and azoxystrobin have been shown to provide 50% higher yields in treated crops <ref name="seventyseven">{{cite journal|last=Koike|first=Steven T.|coauthors=et al.|date=September-December 2001|title=Rust Disease Continues to Threaten California Garlic Crop|journal=California Agriculture|volume=55|issue=5|pages=35-39}}</ref>.
+==Grapes==
+===Black Rot===
+Black rot is a disease estimated to affect 95% of all eastern [[grape]] vineyards. The USDA estimates it could reduce yields by 85% if left untreated <ref name=fifteen/>. Black rot is spread through spores left in the mummied grapes infected the year before. Upon infection the grapes will shrivel up and turn black <ref name=seventyeight> Pearson, R.C., Black Rot Grape IPM Disease Identification Sheet No. 4, New York State Agricultural Experiment Station, 1984. </ref>. These grapes will not fall from the vine but instead will stay attached and over the winter spores grow within the infected grape. When summer comes the rain will re-moisten the dried up grape and cause it to swell. Spores will discharge from the swollen grape into the air and infect the healthy crop <ref name="seventynine">{{cite journal|last=Ferrin|first=Donald M.|coauthors=D.C. Ramsdell|date=1977|title=Ascospore Dispersal and Infection of Grapes by Guignardia bidwellii, the casual Agent of Grape Black Rot Disease|journal=Phytopathology|volume=67|pages=1501}}</ref>. Prior to fungicide development for black rot in favorable conditions losses of 70 to 100 percent of the crop were common <ref name=seventynine/>. Today however applications of fungicides have been able to give almost complete control of the disease. In many vineyards infections can be reduced from 95% down to 1% <ref name="eighty">{{cite journal|last=Ellis|first=M.A.|coauthors=L.V. Madden and L.L. Wilson|date=October 1986|title=Electronic Grape Black Rot Predictor for Scheduling Fungicides with Curative Activity|journal=Plant Disease|volume=70|issue=10|pages=938}}</ref>.
+===Botrytis Bunch Rot===
+Cold and wet climates favor this disease, which is why it is often found in the coastal vineyards of California and [[New York]] <ref name="eightyone">{{cite journal|last=Pearson|first=R.C.|coauthors=D.G. Riegel|date=1983|title=Control of Botrytis Bunch Rot of Ripening Grapes: Timing Applications of the Dicarboximide Fungicides|journal=American Journal of Enology and Viticulture|volume=34|issue=3|pages=167}}</ref>. In the eastern vineyards this disease is estimated to infect 30% of grapes while in California it can infect up to half <ref name="eightytwo">{{cite journal|last=McClellan|first=W.D.|coauthors=et al|date=1973|title=Early Botrytis rot of Grapes and its Control|journal=American Journal of Enology and Viticulture|volume=24|issue=1|pages=27}}</ref>. This can reduce yields by 40-60% <ref name=fifteen/> <ref name="eightythree">{{cite news|title=Botrytis is an Ever-Present Threat in Winegrapes|date=May 10, 1995|publisher=Ag Alert}}</ref>. Much like black rot, bunch rot overwinters in the berries and will infect the next season’s crop through spore ejections in the summer <ref name="eightyfour">{{cite news|title=Botrytis Bunch Rot: Understanding The Disease, Strategies for Control|last=Pearson|first=Roger c.|date=August 1979|publisher=Eastern Grape Grower and Winery News|pages=18}}</ref>. Originally [[Bordeaux mixture]]was used to controlled botrytis bunch rot but the use of synthetic chemicals is now the preferred method <ref name="eightyfive">{{cite journal|last=Braun|first=Alvin J.|date=1949|title=Some Effects of Fermate and Bordeaux sprays on Concorn Grapes|journal=Phytopathology|volume=39|pages=3}}</ref>.
+===Phomopsis Cane and leaf spot===
+Cane and leaf spot is a disease found rarely in California but on large areas of the East coast. The USDA estimates it affects 75% of the acres of eastern vineyards with the potential to reduce yields up to 15% <ref name=fifteen/>. The disease can result in lesions, defoliation, and berry rot. However the same fungicide sprays used to control black rot done early in the season have been shown to control cane and leaf spot.
+===Powdery Mildew===
+Powdery mildew was first reported in European grape vineyards in the mid 1850’s. It could reduce yields by up to 80%.  In [[France]] alone it reduced [[wine]] production from a billion gallons to only two hundred million gallons <ref name="eightysix">{{cite book|last=Carefoot|first=G.L.|coauthors=E.R. Sprott|title=Famine on the Wind: Man's Battle Against Plant Disease|publisher=Rand McNally & Company|date=1967}}</ref>. It was as a result of this disease’s rapid spread throughout the continent that the first fungicide, sulfur, was discovered <ref name="eightyseven">{{cite book|last=Spencer|first=D.M.|title=The Powdery Mildews|publisher=Academic Press|location=New York|date=1978}}</ref>. The success of sulfur was so great that the grape industry was sparked in California when it was seen that disease could now be controlled and grapes now easy to grow. Powdery mildew if uncontrolled will rot the grapes from the inside out. Powdery mildew slows the growth of the grape skin so that the inside pulp grows at a faster rate and bursts through. These split grapes then dry up and rot <ref name="eightyeight">{{cite book|last=Pearson|first=Roger C.|coauthors=Austin C. Goheen|title=Compendium of Grape Diseases|publisher=APS Press|date=1988}}</ref>. For the grapes that manage to not split open they are of a much lower quality than normal grapes. Their acidity is much higher and as a result the wines will taste bitter and off flavor to most wine drinkers <ref name="eightynine">{{cite journal|last=Ough|first=C.S.|coauthors=H.W. Berg|date=1979|title=Research Note: Powdery Mildew Sensory Effect on Wine|journal=American Journal of Enology and Viticulture|volume=10|issue=4|pages=321}}</ref>. In order to control powdery mildew the same treatment that was recommended in the late 1800’s is still used today: regular applications of sulfur every 1-2 weeks <ref name=ninety> Bioletti, Frederic T., Oidium or Powdery Mildew of the Vine, University of California, Agricultural Experiment Station, Bulletin No. 186, February, 1907 </ref>.
+==Green Beans==
+===Alternaria===
+Alternaria was first reported on [[green beans]] in Florida in 1951 after a hundred acres were lost to the disease in one season <ref name="ninetyone">{{cite journal|last=Swank|first=George Jr.|date=July 15, 1951|title=Alternaria Leaf Spot and Dieback of Snap Bean: A New Disease in Central Florida|journal=Plant Disease Reporter|volume=35|issue=7|pages=330}}</ref>. By the 1970s it had spread up the coast to New York <ref name="ninetytwo">{{cite journal|last=Abawi|first=G.S.|coauthors=D.C. Crosier and A.C. Cobb|date=November 1977|title=Pod-Flecking of Snap Beans Caused by Alternaria alternata|journal=Plant Disease Reporter|volume=61|issue=1|pages=901}}</ref>. The disease causes lesions on the skin of the green bean to grow, killing the tissue and giving the plant a moldy appearance <ref name="ninetythree">{{cite book|last=Hall|first=Robert|title=Compendium of Bean Diseases|publisher=APS Press|date=1991}}</ref>. However trials have shown that applications of [[chlorothalonil]] can reduce alternaria by up to 85% <ref name=ninetytwo/>
+===Bacterial Blight===
+Bacterial blight is endemic to green bean crops grown east of the [[Rocky Mountains]] <ref name=sixtythree/>. During ideal conditions (usually humid weather) the disease can inflict losses as high as 60% <ref name="ninetyfour">{{cite web|url=http://ipcm.wisc.edu/piap/snapbeans/default.htm|title=Processing Snap Bean Production: A Biologic and Economic Assessment of Pest Management and Pesticide Usage|last=Delahunt|first=Karen A.|coauthors=Susan E. Rice and Jeffery A. Wyman|date=1997|publisher=University of Wisconsin}}</ref>. Symptoms include lesions resemble burn marks that gradually grow larger <ref name=ninetythree/>. In some states incidence of the disease can be as high as 100% <ref name="ninetyfive">{{cite web|url=http://pestdata.ncsu.edu/cropprofiles/docs/FLsnapbeans.html|title=Crop Profile for Beans (Snap) in Florida|date=March 2003|publisher=USDA}}</ref>. Trials have shown that properly timed copper sprays can reduce incidence by 90% <ref name="ninetysix">{{cite journal|last=Oshima|first=N.|coauthors=L.E. Dickens|date=July 1971|title=Effects of Copper Sprays on Secondary Spread of Common Bacterial Blight of Beans|journal=Plant Disease Reporter|volume=55|issue=7|pages=609}}</ref>.
+===Root Rot===
+Root rot is a common disease of Florida green beans and can reduce crop yields there by up to 75% if untreated <ref name=ninetyfive/>. It was not until the 1950s that an effective fungicide was found to control root rot. Trials in Florida in the 1950s showed that applications of PCNB were able to reduce incidence down to 3% <ref name="ninetyseven">{{cite journal|last=Moore|first=W.D.|coauthors=Robert A. Conover|date=February 15 1955|title=Chemical Soil Treatments for the Control of Rhizoctonia on Snap Beans|journal=Plant Disease Reporter|volume=39|issue=2|pages=103}}</ref>. PCNB is still the primary treatment today <ref name="ninetyeight">{{cite journal|last=Crosson|first=D.F.|coauthors=et al.|date=February 15 1963|title=Control of Rhizoctonia root-Rot of Snapbean: Low Volume in-the-furrow Versus High Volume Preplant Fungicidal Sprays|journal=Plant Disease Reporter|volume=47|issue=2|pages=109}}</ref>.
+===Powdery Mildew===
+Powdery mildew appears on the green bean plant as a white mold on the surface of the green bean leaf. This grows and can cover the entire plant with this powdery fungal growth <ref name=ninetythree/>. Yield losses occur because the damage makes the crop not commercially viable <ref name=sixtythree/>. However powdery mildew can be controlled with applications of sulfur. The original trials in the 1930s showed that incidence could be reduced from 87% to 2% <ref name="ninetynine">{{cite journal|last=Moore|first=W.D.|date=1936|title=Powdery Mildew (erysiphe polygoni) on Garden Snap Beans|journal=Phytopathology|volume=26|pages=1135}}</ref>.
+===Rust===
+Bean rust is a disease of the green bean that causes rust-color pustules on the leaves of the plant. These pustules eventually rupture and eject thousands of spores into the air to be carried to other plants <ref name=sixtythree/>. Each individual spore can produce a fresh pustule on a plant within a week; therefore rust can rapidly reach epidemic levels if left untreated <ref name=sixtythree/>. When leaves become infected with rust they will rapidly die causing defoliation. However research in the 1930s discovered that sulfur was an effective treatment for rust and since then yield losses due to rust is now reduced by 60% in treated fields <ref name="hundred">{{cite journal|last=McMillan Jr.|first=R.T.|coauthors=G. Ellal and H.H. Bryan|date=1982|title=Fungicides for the Control of Squash Powdery Mildew and Bean Rust|journal=Proceedings of the Florida State Horticultural Society|volume=95|pages=304-307}}</ref>.
+===White Mold===
+Before effective fungicides were developed white mold caused significant hardship for green bean growers. White mold is considered a resilient disease. After infecting the plant the white mold will produce black formations called sclerotia that fall to the soil and can survive in the soil for over five years until the conditions are right for infection again <ref name="hundredone">{{cite journal|last=Steadman|first=James R.|date=April 1983|title=White Mold - A Serious Yield Limiting Disease of Bean|journal=Plant Disease|volume=67|issue=4|pages=346}}</ref>. Since white mold affects plants very late in the growing season farmers would often harvest early in order to avoid losing much of their crop. However this usually resulted in a 30% loss of crop. Research in the 1970s eventually discovered that fungicides applied every 20 days reduced white mold incidence to 0% in treated areas <ref name="hundredtwo">{{cite journal|last=Natti|first=J.J.|date=June 1971|title=Epidemiology and Control of Bean White Mold|journal=Phytopathology|volume=61|issue=6|pages=669}}</ref>
+==Hazelnuts==
+===Eastern filbert blight===
+Eastern filbert blight or EFB was first introduced to U.S. [[hazelnut]] orchards through imported European hazelnut trees in the 1920s. By the 1970s this disease had spread all the way from its New York origins to the west coast. In hazelnuts the EFB will cause cankers to form on the tree and will slowly expand and kill the tree over the course of several years if diseased tree limbs are not removed in time <ref name="hundredthree">{{cite journal|last=Johnson|first=Kenneth B.|coauthors=et al.|date=December 1996|title=Eastern Filbert Blight of European Hazelnut: It's Becoming a Managable Disease|journal=Plant Disease|volume=80|issue=12|pages=1308-1316}}</ref>. Research with chlorothalonoil and tebuconozole in the 1990s showed that 4-5 applications of the fungicides on a 2 week schedule when vegetative buds are breaking dormancy is ideal for control of EFB <ref name="hundredfour">{{cite journal|last=Johnson|first=Kenneth B.|coauthors=Jay W. Pscheidt and John N. Pinkerton|date=August 1993|title=Evaluation of Chlorothalonoil, Fenarimol, and Flusilazole for Control of Eastern Filbert Blight|journal=Plant Disease|volume=77|issue=8|pages=831-837}}</ref>. The state of Oregon has estimated that if left uncontrolled EFB could eliminate half of the state’s hazelnuts within ten years <ref name=hundredfive> Specific Exemption for Use of Tebuconazole (Elite 45 DF Foliar Fungicide) for Control of Eastern Filbert Blight in Hazelnuts in Oregon, Oregon Department of Agriculture, Section 18 Emergency Exemption Request, December 20, 1999 </ref>.
+==Hot peppers==
+New Mexico accounts for the vast majority of U.S. hot [[pepper]] production. It is the number one producing state and accounts for roughly 65% of all U.S. hot pepper production.
+===Bacterial Spot===
+Bacterial spot is spread from plant to plant through water, wind, and plant contact. Once infected, the leaves of the plant are targeted by the disease. The disease causes severe spotting of the pepper and kills the leaves of the plant <ref name="hundredsix">{{cite web|url=http://www.ipmcenters.org/cropprofiles/docs/nmpeppers-chili.html|title=Crop Profile for Peppers (Chile) in New Mexico|date=March 2000|publisher=USDA}}</ref>. This is a twofold problem because the defoliation of the plant will result in the pepper being discolored by sunscald. Research for bacterial spot treatment has shown that copper sprays have been able to increase marketable yields by 50% in treated fields <ref name="hundredseven">{{cite journal|last=Crossan|first=DF|coauthors=et al|date=April 15, 1963|title=A Comparison of Fixed Copper and Dodine sprays with Various Additives for control of Bacterial Spot of Pepper Fruit|journal=Plant Disease Reporter|volume=47|issue=4|pages=239}}</ref>.
+===Powdery Mildew===
+Powdery mildew causes a white powdery growth to cover the leaves of the hot pepper plant. These leaves may drop prematurely and as with bacterial spot can then cause sunscald <ref name="hundredeight">{{cite book|last=Pernezny|first=Ken|coauthors=et al.|title=Compendium of Pepper Diseases|publisher=APS Press|date=2003}}</ref>. This disease has been known to cause yield losses as high as 50-60% in untreated fields <ref name="hundrednine">{{cite journal|last=Smith|first=Richard f.|coauthors=et al.|date=November-december 1999|title=Several Fungicides Control Powdery Mildew in Peppers|journal=California Agriculture|volume=53|issue=6|pages=40}}</ref>. The prime fungicide used to control powdery mildew is myclobotinil.
+==Lettuce==
+===Bottom Rot===
+Bottom rot symptoms consist largely of deep reddish colored lesions on the leaves that slowly spread from leaf to leaf until the entire head is rotted <ref name=sixtythree/>. Trials with vinclozolin have demonstrated effectiveness in controlling bottom rot. Research indicated that when treated, crop yields will rise about 36% <ref name="hundredten">{{cite journal|last=Riedel|first=R.M.|coauthors=L.J. Herr and P.J. Dudash|date=1990|title=Chemical and Biological Control of Bottom Rot of Lettuce|journal=Fungicide and Nematicide Tests|volume=45|pages=113}}</ref>.
+===Downy Mildew===
+Downy mildew is an extremely common disease of the [[lettuce]] plant. This is largely due to the diseases’ quick germination period, three hours, and the lettuce plant being susceptible at all growth stages. One study estimated that in untreated Florida fields 75% of lettuce was infected with downy mildew and considered unsalable <ref name="hundredeleven">{{cite journal|last=Raid|first=R.N.|coauthors=L.E. Datnoff|date=1989|title=Efficacy of Fosetyl-AL Foliar Application in Controlling Downy Mildew of Lettuce|journal=Proceedings of the Florida State Horticultural Society|volume=102|pages=362}}</ref>. Research with maneb has shown the ability to reduce the number of lesions per 10 plants from 187 to about one <ref name=hundredtwelve> Greathead, Arthur S., et al, “Fungicidal Control of Downy Mildew and Anthracnose of Lettuce,” Iceberg Lettuce Research Program, 6th Annual Report, University of California, 1980 </ref>. EBDC and fosetyl-al have also been shown effective in Florida trials that reduced unmarketable heads to 2% after fungicidal treatments <ref name=hundredeleven/>.
+===Lettuce Drop===
+Lettuce drop is another resilient disease of the lettuce plant. It can be found in all lettuce growing regions of the U.S. and is able to survive in the soil for up to a decade once the disease infects a field <ref name="hundredthirteen">{{cite book|last=Davis|first=Michael R.|coauthors=et al.|title=Compendium of Lettuce Diseases|date=1997}}</ref>. The fungus appears on the plant as a white mass on the leaf that slowly turns into a hard black growth. These growths release spores that infect the lettuce plant with pathogens that slowly move up the stalk of the plant killing tissue as it travels <ref name=sixtythree/> <ref name=hundredthirteen/>. Use of DCNA, iprodione, and vinclozolin about a month before harvest has been shown to significantly reduce lettuce drop in treated fields <ref name=hundredthirteen/>. In treated California fields fungicides are able to reduce yield losses as low as 5% <ref name="hundredfourteen">{{cite web|url=http://www.ipmcenters.org/pmsp/pdf/CAAZLettuce.pdf|title=Pest Management Strategic Plan for California and Arizona Lettuce Production|date=February 2003|publisher=USDA}}</ref>.
+===Powdery Mildew===
+Powdery mildew attacks lettuce plants by robbing them of the nutrients within the leaf. The fungus appears as a white growth on the upper surface of the leaf where it will uses small tubes to pull nutrients out of the plant <ref name=sixtythree/>. This causes severe discoloration and eventual defoliation of the plant. Applications of sulfur are recommended as the primary way to control powdery mildew on lettuce <ref name=hundredthirteen/>.
+==Onions==
+===Downy Mildew===
+Downy mildew is an extremely fast developing disease in the [[onion]]. Studies have observed up to 40% of a field being infected in less than three days <ref name=hundredfifteen>Onion Downy Mildew, University of California Cooperative Extension Service, March, 1995 </ref>. The first symptoms of the disease are white and purple growths on the surface of the plant leaves. Eventually these leaves die. This in turn destroys the plant’s photosynthetic abilities and stunts the growth and sometimes kill the plant <ref name="hundredsixteen">{{cite journal|last=Yarwood|first=C.E.|coauthors=Onion Downy Mildew|date=February 1943|title=Onion Downy Mildew|journal=Hilgardia|volume=14|issue=11}}</ref>. If left unchecked downy mildew has the capability of reducing yields by 65% <ref name="hundredseventeen">{{cite web|url=http://pestdaa.ncsu.edu/cropprofiles/docs/txonions.html|title=Crop Profile for Onion in Texas|date=June 2003|publisher=USDA}}</ref>. Downy mildew is controlled with the same foliar fungicides as leaf blight: azoxystrobin, copper, mancozeb, maneb, and mefenoxam.
+===Botrytis Leaf Blight===
+Leaf blight occurs in areas with hot and humid weather. The leaf blight spores land on onion leaves, penetrate the skin, and rapidly kill the leaf. This causes a severe reduction in bulb size, as high as 50%, and can happen in less than a week <ref name="hundredeighteen">{{cite journal|last=McLean|first=D.M|coauthors=Bailey Smith|date=1959|title=Tip and Leaf Blight of Onions in the Lower Rio Grande Valley|journal=Journal of the Rio Grande Valley Horticultural Society|volume=13}}</ref>. Applications of foliar fungicides can be used to control leaf blight. These include: azoxystrobin, chlorotholonil copper, mancozeb, maneb, and mefenoxam.
+===Purple blotch===
+Symptoms of purple blotch are primarily small white lesions that grow larger as they turn purple and brown. From these lesions spores are produced that cause additional lesions and also spread to other plants. However to develop, the disease requires very wet conditions for an extended period of time <ref name=hundredseventeen/>. Fungicide treated fields have been found to have yields roughly 20-35% higher as opposed to untreated fields <ref name="hundrednineteen">{{cite web|url=http://pestdata.ncsu.edu/cf/cropprofiles/Detail.CFM?FactSheets_RecordID=33|title=Crop Profile for Onions in Wisconsin|date=January 1999|publisher=USDA}}</ref>
+===Seed rot===
+Yield loss due to seed rot can be as high as 30% in heavily infected acres <ref name="hundredtwenty">{{cite web|url=http://pestdata.ncsu.edu/cf/cropprofiles/Detail.CFM?FactSheets_RecordID=94|title=Crop Profile for Onions in New York|date=May 1999|publisher=USDA}}</ref>. The disease infects the onion seed and will cause the onions roots to be gray and mushy. These roots and plants will rapidly decay and decompose, killing the plant <ref name="hundredtwentyone">{{cite book|last=Schwartz|first=Howard F.|coauthors=S. Krishna Mohan|title=Compendium of Onion and Garlic Diseases|publisher=APS Press|date=1995}}</ref>. Mefenoxam is recommended as treatment for seed rot.
+===Smut===
+[[Smut]] is a tough disease of the onion because it can last for years in the soil as spores. When the onion crop is planted the spores will germinate and enter the fresh seeds <ref name=hundredtwenty/>. When the plant grows lesions will form on the leaf and any bulbs that form will be covered in black spots. Most of the time infected seeds will die within 3-5 weeks of planting <ref name=hundredtwenty/>. Mancozeb is recommended for treatment of smut.