Beans:Diagnostics

BEAN PESTS AND NUTRITIONAL DISORDERS

ALFALFA MOSAIC (AMV)

‘‘‘Alfalfa Mosaic (AMV) ‘‘‘ This disease is characterized by symptoms that include stunting, leaf and pod deformation, drying of stems and leaves, and yellowing. Little research has been done on the control of alfalfa mosaic in beans, because the disease is relatively minor. (Disease Caused by Viruses)

ALTERNARIA LEAF AND POD SPOT (ALTERNARIA SPP)

‘‘‘Alternaria Leaf and Pod Spot (Alternaria spp.) ‘‘‘ This disease is characterized by small flecks or tiny water-soaked spots that appear on infected green leaves and pods. Lesions that develop on leaves appear as circular to irregular spots and flecks with a pale brown center and a dark brown margin surrounded by a yellow halo. The lesions may develop concentric rings, and diseased tissue may become dry and brittle and fall out, leaving a shot hole in the leaf. Control of the disease on snap bean pods involves the use of wider plant and row spacing, fungicides, resistant cultivars, and crop rotation. (Fungal Disease of Leaf and Stem)

ANGULAR LEAF SPOT (PHAEOISARIOPSIS GRISEOLA)

‘‘‘Angular Leaf Spot (Phaeoisariopsis griseola) ‘‘‘ This disease is characterized by lesions that develop on the leaf that are gray or brown irregular spots that may be bordered by a yellow halo. As the disease progresses, these lesions may group together, the plant becomes yellow, and drying leaves may fall off prematurely. The best form of control includes using pathogen-free seed that has been treated with an effective fungicide, rotating the crop where possible, and using resistant cultivars where available. (Fungal Disease of Leaf and Stem)

ANTHRACNOSE (GLOMERELLA LINDEMUTHIANA)

‘‘‘Anthracnose (Glomerella lindemuthiana) ‘‘‘ This disease is characterized by small, dark brown to black lesions that usually appear on leaf petioles and on the lower surfaces of leaves and leaf veins. The lesions are elongate, angular, and brick red to purple, becoming dark brown to black. Infected seeds are often discolored and may contain dark brown to black cankers. The best form of control is to use resistant cultivars where available and to apply seed treatments, including benomyl and thiophanate methyl. (Fungal Disease of Leaf and Stem)

APHANOMYCES ROOT AND HYPOCOTYL ROT (APHANOMYCES EUTEICHES PV PHASEOLI)

‘‘‘Aphanomyces Root and Hypocotyl Rot (Aphanomyces euteiches pv phaseoli) ‘‘‘ This disease is characterized by lesions that develop on the roots that reproduce and spread to the entire root system. The lesions are initially yellow-brown and fairly firm and cause the roots to become softer as the pathogen destroys the cortex. The disease usually grows upward along the hypocotyl to produce a lesion above the soil line which is slightly water-soaked and gray-green. This tissue turns brown as it dries out. The best form of control is have the soil tested in a laboratory for its root rot potential and avoid planting in any infested fields. (Fungal Disease of Roots)

ASCOCHYTA LEAF SPOT (PHOMA EXIGUA PV EXIGUA)

‘‘‘Ascochyta Leaf Spot (Phoma exigua pv exigua) ‘‘‘ This disease is characterized by brown to black lesions that develop on the leaves. These lesions may have concentric zones that are 10-30 mm in diameter and contain small, black pycnidia. Dark gray to black lesions may also appear on the branches, stems, nodes, and pods causing the plant to become girdled and die. Infected seeds turn brown to black. The best forms of control include using fungicide sprays and rotating the beans with nonhost crops such as cereal or corn. (Fungal Disease of Leaf and Stem)

ASHY STEM BLIGHT (MACROPHOMINA PHASEOLINA)

‘‘‘Ashy Stem Blight (Macrophomina phaseolina) ‘‘‘ This disease is characterized by wilting, yellowing, and death of the leaves that may only appear on one side of the plant. Lesions also develop on the seedling stem at the soil line during emergence and they are small, irregularly shaped, blackish, and sunken. Wilting, yellowing, and death of leaves may be more pronounced on one side of the plant. The best form of control is to use resistant cultivars where available, use pathogen-free seed, apply chemical treatment to the seed, and fumigate the soil. (Fungal Disease of Leaf and Stem)

BACTERIAL BROWN SPOT (PSEUDOMONAS SYRINGAE PV SYRINGAE)

‘‘‘Bacterial Brown Spot (Pseudomonas syringae pv syringae) ‘‘‘ This disease is characterized by lesions that develop on the leaves and are circular, brown, show areas of drying and are often surrounded by a bright yellow zone. Pods that become infected may be twisted or bent where the lesions develop. The best form of control includes using resistant cultivars and pathogen-free seed. (Disease Caused by Bacteria)

BACTERIAL WILT (CURTOBACTERIUM FLACCUMFACIENS PV FLACCUMFACIENS)

‘‘‘Bacterial Wilt (Curtobacterium flaccumfaciens pv flaccumfaciens) ‘‘‘ This disease is characterized by soft, wilting leaves during warm, dry weather. Infected seeds may show purple or yellow discoloration and struggle to grow properly. If the disease is found, pathogen-free seed and control measures recommended for other bacterial diseases of bean should be used. (Disease Caused by Bacteria)

BEAN COMMON MOSAIC (BCMV)

‘‘‘Bean Common Mosaic (BCMV) ‘‘‘ This disease is characterized by light and dark green mosaic, leaf roll, malformation, yellow dots, and abnormally slow growth habits. The vascular tissues may dry out causing the plant to die if it is still young. The best form of control is the use of resistant cultivars. (Disease Caused by Viruses)

BEAN CURLY DWARF MOSAIC (BCDM)

‘‘‘Bean Curly Dwarf Mosaic (BCDM) ‘‘‘ This disease is characterized by leaf malformation causing the edges to become rugged and curled and mosaic. Highly susceptible bean cultivars may show dwarfing, increased leaf growth, and proliferation. The most severe symptom occurs when the top of the plant dries out which immediately kills the plant. The best form of control is the use of chrysomelid beetle. (Disease Caused by Viruses)

BEAN DWARF MOSAIC (BDM)

‘‘‘Bean Dwarf Mosaic (BDM) ‘‘‘ This disease is characterized by young developing plants that are severely stunted, have shortened internodes, leaf malformation, flower abortion and pod distortion. The best form of control is to use resistant cultivars if they are available and to avoid host plants that are favored by whitefly is highly recommended, especially soybean, tobacco, tomato, potato, and eggplant. (Disease Caused by Viruses)

BEAN GOLDEN MOSAIC (BGMV)

‘‘‘Bean Golden Mosaic (BGMV) ‘‘‘ This disease is characterized by fine, bright yellow lines that occur only in the veins of the leaves. The leaves curl and fail to expand properly and develop stiff and leathery surfaces. Leaves that may become completely yellow are usually distorted and may dry up. The best form of control is to use resistant cultivars and control whitefly vectors. (Disease Caused by Viruses)

BEAN MILD MOSAIC (BMMV)

‘‘‘Bean Mild Mosaic (BMMV) ‘‘‘ This disease is not a problem if it occurs by itself, but when combined with other viruses the results are quite severe. There are resistant cultivars for some varieties of bean, but not for the common bean. (Disease Caused by Viruses)

BEAN POD MOTTLE (BPMV)

‘‘‘Bean Pod Mottle (BPMV) ‘‘‘ This disease is characterized by malformed pods that contain poorly developed seeds. The leaves may also become infected and are malformed with mild to severe mosaic. Most bean cultivars show resistance to bean pod mottle which is the best form of control. It is also helpful to avoid virus-infected seed, control perennial weeds, and eliminate overwintering beetles. (Disease Caused by Viruses)

BEAN RUGOSE MOSAIC (BRMV)

‘‘‘Bean Rugose Mosaic (BRMV) ‘‘‘ This disease is characterized by stunted plants and leaves that are deformed, rugged, and show severe mosaic. The pods may also be spotted and be malformed. The best form of control is to use resistant cultivars. (Disease Caused by Viruses)

BEAN YELLOW MOSAIC (BYMV)

‘‘‘Bean Yellow Mosaic (BYMV) ‘‘‘ This disease is characterized by either mild and diffuse yellow spotting with limited plant stunting, or coarse mosaic, rugosity, malformation, and severe stunting. Some cultivars may also develop dry spots, veinal and apical drying, wilting, and premature death. The best form of control is to use resistant cultivars. (Disease Caused by Viruses)

BEAN YELLOW STIPPLE (BYSV)

‘‘‘Bean Yellow Stipple (BYSV) ‘‘‘ This disease is characterized by small, light yellow spots that are found on the trifoliate leaves that form the yellow stippling or mottle. There are no control measures at this time for the disease and resistance is not available. (Disease Caused by Viruses)

BLACK ROOT ROT (THIELAVIOPSIS BASICOLA)

‘‘‘Black Root Rot (Thielaviopsis basicola) ‘‘‘ This disease is characterized by elongated, narrow lesions that develop on the hypocotyl and root tissues. These lesions are initially reddish purple in color, then become dark charcoal to black. As the disease progresses, the lesions often group together and form large black areas. The best forms of control include using resistant cultivars and apply soil fungicides. (Fungal Disease of Roots)

BORON DEFICIENCY

‘‘‘Boron Deficiency ‘‘‘ Boron deficiency is rare in beans, but may occur on coarse-textured soils with low organic matter content. Boron deficiency is characterized by crinkled, thickened, and leathery leaves. An early symptom is reduced growth or death of the apical meristem resulting in profuse lateral branches whose terminal buds die. Stems may be swollen near the nodes. Flowers and pods either do not form or they abort. The root system develops poorly. Boron deficiency is corrected by application of soluble boron salts. Beans are very sensitive to excess boron. Boron fertilizer rates are generally 0.5 lbs boron/acre or less. Because of potential toxicity, band applications are not recommended. Beans planted on soils with high boron may show toxicity symptoms which generally appear as firing of the leaf margins resembling salt injury. (Noninfectious Disorder -- Nutritional Disorder)

CALCIUM DEFICIENCY

‘‘‘Calcium Deficiency ‘‘‘ Calcium deficiency is not commonly observed in beans. Most soils where beans are produced contain adequate calcium or are limed to raise soil pH. Deficiency symptoms include loss of turgor, death of growing points, and yellowing of young leaves. Pods may be soft and seeds may fail to develop. Calcium is a key component of cell walls and membranes. Deficiency is prevented by liming or application of soluble calcium salts such as gypsum. (Noninfectious Disorder -- Nutritional Disorder)

CERCOSPORA LEAF SPOT AND BLOTCH (CERCOSPORA CANESCENS AND CRUENTA)

‘‘‘Cercospora Leaf Spot and Blotch (Cercospora canescens and cruenta) ‘‘‘ This disease is characterized by brown or rust colored lesions that develop on the leaves. These lesions may vary in shape from circular to angular and have a diameter of 2-10 mm depending on if the lesions group together. The lesions may also have a gray center with a slightly reddish border and severely affected leaves turn yellow. The best form of control is to use resistant cultivars. (Fungal Disease of Leaf and Stem)

CHAETOSEPTORIA LEAF SPOT (CHAETOSEPTORIA WELLMANII)

‘‘‘Chaetoseptoria Leaf Spot (Chaetoseptoria wellmanii) ‘‘‘ This disease is characterized by lesions that develop on the leaves that are irregular to circular, ash gray in color, medium to large in size and may have a diameter of approximately 10 mm with a reddish border and gray to black pycnidia in the center. The best form of control is to rotate the crop with nonhost crops for about 5 years. (Fungal Disease of Leaf and Stem)

CLOVER YELLOW VEIN (CYVV)

‘‘‘Clover Yellow Vein (CYVV) ‘‘‘ This disease is characterized by stunted plants that are malformed and have a yellow mosaic. Most plants also show apical drying, premature defoliate, and wilting that result in the death of the plant. The best form of control is the use of resistant cultivars. (Disease Caused by Viruses)

COMMON BACTERIAL BLIGHT (XANTHOMONAS CAMPESTRIS PV PHASEOLI)

‘‘‘Common Bacterial Blight (Xanthomonas campestris pv phaseoli) ‘‘‘ This disease is characterized by water-soaked spots that develop on the leaves. These spots gradually enlarge, becoming spongy and they dry out leaving a border of bright yellow tissue. Lesions can also be found at the margin and in areas between the veins of the leaf. The best forms of control include using resistant cultivars and spraying foliage with a copper-based bactericide. (Disease Caused by Bacteria)

COPPER DEFICIENCY

‘‘‘Copper Deficiency ‘‘‘ Copper deficiency, though rare, is most often observed in sandy, organic, or over-limed soils. Copper deficiency is characterized by stunted plants with shortened internodes and necrotic areas adjacent to the veins near the base of the leaflet. Leaves may show scorching, wilting, and senescence. Copper deficiency is prevented by application of soluble copper fertilizers, such as copper sulfate or copper EDTA. Fertilizer rates are generally about one lb Cu/acre. Rates of 2-3 lbs copper/acre may be effective for several years, but these rates should be broadcast not banded. Foliar sprays of copper sulfate or copper EDTA are also effective. (Noninfectious Disorder -- Nutritional Disorder)

CUCUMBER MOSAIC (CMV)

‘‘‘Cucumber Mosaic (CMV) ‘‘‘ This disease is characterized by curling, green or yellow spots, and blisters that develop on the leaves, and a dark green veinbanding, zipper-like appearance along the main veins. Plants that are flowering and become infected mostly show small, curved, spotted pods, but may also develop the other leaf symptoms in the apical leaves. The best form of control is to use virus-free seed and avoid planting in fields that may be infected or show signs of getting the disease. (Disease Caused by Viruses)

CURLY TOP (BCTV)

‘‘‘Curly Top (BCTV) ‘‘‘ This disease is characterized by a tight curl of the first trifoliate bud tips and yellowing of the trifoliolate leaf. As the disease progresses, the primary leaf also turns yellow and the plant dies. The best form of control is to use resistant cultivars. (Disease Caused by Viruses)

DOWNY MILDEW (PHYTOPHTHORA NICOTIANAE)

‘‘‘Downy Mildew (Phytophthora nicotianae) ‘‘‘ This disease is characterized by lesions that develop on leaves and petioles and appear as white spots that enlarge and eventually cause the leaves to wilt and die. Major damage occurs as pods become infected and become covered by white, cottony patches of mycelium. Blossoms, buds, and other plant parts may also be killed if they are infected with the white mycelium. The best form of control is to use resistant cultivars, especially with lima beans, and applying a fungicide spray during flowering and pod formation. (Fungal Disease of Leaf and Stem)

ENTYLOMA LEAF SMUT (ENTYLOMA SPP)

‘‘‘Entyloma Leaf Smut (Entyloma spp.) ‘‘‘ This disease is characterized by round or oval lesions that appear water-soaked and become gray-brown on the upper leaf surface and gray-blue on the lower leaf surface. Infected leaves exhibit a blister smut that appears as dark swellings on the upper leaf surface. The best form of control is to rotate the crop with nonhost crops such as cereals and corn. (Fungal Disease of Leaf and Stem)

FLOURY LEAF SPOT (MYCOVELLOSIELLA PHASEOLI)

‘‘‘Floury Leaf Spot (Mycovellosiella phaseoli) ‘‘‘ This disease is characterized by light green to slightly yellow lesions that develop on the upper leaf surface. The lesions may be circular to angular and have a diameter of 10-15 mm. On the lower leaf surface, white, floury mats of conidiophores and conidia form and a heavy infection may cause defoliation. The best form of control is to apply chemical sprays such as benomyl and thiophanate methyl. (Fungal Disease of Leaf and Stem)

FUSARIUM ROOT ROT (FUSARIUM SOLANI)

‘‘‘Fusarium Root Rot (Fusarium solani) ‘‘‘ This disease is characterized by long, narrow, red to brown streaks that appear on hypocotyls and taproots of 7 to 10 day old seedlings. Plants that are established and become infected are usually stunted, vary in size and vigor creating an uneven top canopy, and depend on less important roots for survival. The best form of control is to practice good cultural control habits. (Fungal Disease of Roots)

FUSARIUM YELLOWS (FUSARIUM OXYSPORUM PV PHASEOLI)

‘‘‘Fusarium Yellows (Fusarium oxysporum pv phaseoli) ‘‘‘ This disease is characterized by premature falling off of the lower leaves and yellowing of the leaves beginning just above the lowest leaves on the stem and progressing upward. As the disease progresses, the leaves become increasingly yellow until finally the plant is a bright yellow color. Plants become stunted if they become infected while they are still young. The best form of control is to use resistant cultivars where available. (Fungal Disease of Leaf and Stem)

GRAY LEAF SPOT (CERCOSPORA VANDERYSTI AND CASTELLANII)

‘‘‘Gray Leaf Spot (Cercospora vanderysti and castellanii) ‘‘‘ This disease is characterized by light green to yellow lesions that develop on the surface of the leaves. The lesions may be angular in shape, 2-5 mm in diameter on the upper leaf surface, and may group together and later become covered by the free, powdery, grayish white growth of the fungus. Resistant cultivars are the best form of control. (Fungal Disease of Leaf and Stem)

GREY MOLD (BOTRYOTINIA FUCKELIANA)

‘‘‘Grey Mold (Botryotinia fuckeliana) ‘‘‘ This disease is characterized by lesions that are dark, water-soaked or translucent, soft and slimy and often develop zones of concentric rings. These lesions may girdle the stem or petiole in which case the distal parts of the plant are invaded and the plant collapses. As diseased tissues dry out, characteristic conidiophores and conidia are formed in a gray-brown, powdery mass, and sclerotia may be formed on bulky tissues, such as stems and pods. The best form of control is to use resistant cultivars. (Fungal Disease of Leaf and Stem)

HAIL INJURY

‘‘‘Hail Injury: ‘‘‘ Plants that suffer from hail injury usually have tattered leaves, broken or crushed stems and branches, and long, whitish, bruised areas on stems, branches, petioles, and leaves. (Noninfectious Disease -- Environment)

HALO BLIGHT (PSEUDOMONAS SYRINGAE PV PHASEOLICOLA)

‘‘‘Halo Blight (Pseudomonas syringae pv phaseolicola) ‘‘‘ This disease is characterized by small, water-soaked spots that appear on the lower leaf surface and may develop a zone of yellow-green tissue around the point of infection. Stems and pods are also infected with pods developing red or brown, water-soaked lesions. If these lesions develop on mature, yellow pods, they may be green but exhibit crusty bacterial ooze on the surface. The best form of control is to use resistant cultivars and apply bactericidal sprays containing fixed copper to reduce epiphytic populations and to control secondary disease spread. (Disease Caused by Bacteria)

IRON CHLOROSIS

‘‘‘Iron Chlorosis ‘‘‘ Iron chlorosis, the name given to iron deficiency symptoms, occurs frequently in beans grown on high pH soils containing free calcium carbonate. Iron availability declines rapidly as soil pH increases. Water-logging of the soil worsens the symptoms, but the effect may be temporary and disappear as the soil dries. Iron chlorosis typically occurs on the new leaves as a distinctive yellowing of the tissue between veins while the veins remain green. Severely chlorotic leaves may be almost white and have necrotic areas. The best method of prevention is variety selection. So-called iron-efficient cultivars are less susceptible to chlorosis and should be planted if chlorosis has been observed previously and soil conditions are conducive to development of deficiency. Soil applications of iron fertilizers are generally ineffective in correcting iron deficiency. The most effective corrective treatment is foliar sprays of soluble iron materials, such as iron chelates or ferrous sulfate. A 0.5 to 1.0% solution of ferrous sulfate with a surfactant sprayed in enough water to wet the leaves (about 20 gals/acre) is effective. Multiple applications at 7-14 day intervals may be necessary. (Noninfectious Disorder -- Nutritional Disorder)

LESION NEMATODES (PRATYLENCHUS SPP)

‘‘‘Lesion Nematodes (Pratylenchus spp.) ‘‘‘ This disease is characterized by poorly developed roots that may bear small, brown-black lesions. The plants also are stunted, yellow, wilt and have reduce vigor. The best form of control is to apply chemicals on the plant such as D-D, methyl bromide, Vorlex, chloropicrin, fenamiphos, oxamyl, carbofuran, aldicarb that are broadcasted over the field or applied along the row. (Disease Caused by Nematodes)

LIGHTNING INJURY

‘‘‘Lightning Injury: ‘‘‘ Plants suffering from lightning injury appear in roughly circular areas in the field and are yellow to light brown and die within a few days. The stem pith of these plants may be brown to black. (Noninfectious Disease --Environment)

MACHISMO

‘‘‘Machismo: ‘‘‘ This disease is characterized by flower petals that turn light to dark green, sepals that become elongated, and a corrugated structure resembling a rolled leaf emerges from the unopened floral apex during the reproductive development of the plant. The best form of control is to plant at recommended dates, rotate the crop with nonhost crops, and do not plant with susceptible cultivars. (Disease Caused by Mycoplasmalike)

MAGNESIUM DEFICIENCY

‘‘‘Magnesium Deficiency ‘‘‘ Magnesium deficiency normally occurs on acid soils of low magnesium limed with calcitic limestone. Symptoms normally occur as interveinal chlorosis resembling manganese deficiency except occurring on the lower leaves. Magnesium deficiency is prevented by liming with dolomitic limestone. On high pH soils, or where dolomite is not available, soluble salts of magnesium are effective. Magnesium sulfate or potassium-magnesium sulfate are commonly used. (Noninfectious Disorder -- Nutritional Disorder)

MANGANESE DEFICIENCY

‘‘‘Manganese Deficiency ‘‘‘ Manganese deficiency occurs often in beans grown on high-pH, over-limed, poorly drained, or high organic matter soils. Manganese deficiency is characterized by interveinal chlorosis resembling magnesium deficiency except it occurs on the younger leaves. It may sometimes resemble iron chlorosis. Mild chlorosis may appear as a mottling of the leaf with areas of light green. Manganese deficiency may be prevented by applications of manganese sulfate. Band applications are recommended. Broadcast applications of manganese on high pH soils are not recommended. Manganese EDTA applications on high pH soils have not been effective and in some cases have actually worsened the deficiency. Insoluble manganese fertilizers such as manganese oxide are not effective. Manganese deficiency detected early in the season may be corrected with foliar sprays of manganese sulfate or manganese EDTA. Multiple applications may be necessary. (Noninfectious Disorder -- Nutritional Disorder)

MOISTURE STRESS

‘‘‘Moisture Stress: ‘‘‘ Plants that are suffering from moisture stress are unable to get water to the plant roots, toxic concentrations of ions such as magnesium and boron accumulate in the plant, the stomates remained closed, carbon dioxide in the plant is restricted, and the plant permanently wilts. Plants that receive too much water may have important nutrients leached out, the oxygen content in the plant is reduced, the plant becomes yellow and stunted, and there is an increased level of toxic by- products. (Noninfectious Disease --Environment)

MOLYBDENUM DEFICIENCY

‘‘‘Molybdenum Deficiency ‘‘‘ Molybdenum deficiency can occur in acidic soils of high iron and aluminum content. Molybdenum availability decreases as pH decreases. The only known functions of molybdenum are in nitrogen fixation and nitrate reduction in the plant. Molybdenum deficiency resembles nitrogen deficiency. Molybdenum deficiency is usually prevented by liming acid soils. Because of the extremely small amounts of molybdenum needed by plants, seed treatments of molybdenum fertilizer are the best method of assuring adequate distribution. (Noninfectious Disorder -- Nutritional Disorder)

NITROGEN DEFICIENCY

‘‘‘Nitrogen Deficiency ‘‘‘ Beans are legumes and can fix some of their nitrogen requirement if appropriate strains of Rhizobium are present in adequate populations under good conditions. However, beans are not normally able to fix adequate nitrogen for high yielding crops. Poor aeration, acid soil pH, high levels of nitrate nitrogen, cold soil temperatures, restricted root growth, or poor inoculation can inhibit nitrogen fixation. Nitrogen deficiency may occur on all soils, and beans often respond to modest rates of fertilizer nitrogen. Heavy rain or irrigation can leach available soil nitrogen and induce deficiency. Deficiency symptoms occur as stunted growth, generally yellowing of the entire plant, poor flowering, and poorly filled pods. Nitrogen deficiency can be prevented by applying nitrogen fertilizer at rates ranging from 20 to 90 lbs N/acre depending on soil, environment, and yield level. Modest rates of N can actually increase nitrogen fixation by improving early growth and leaf-area development. (Noninfectious Disorder -- Nutritional Disorder)

PEANUT MOTTLE (PMV)

‘‘‘Peanut Mottle (PMV) ‘‘‘ This disease is characterized by dry, dying lesions that occur on unifoliolate leaves of susceptible plants. Sometimes resistant cultivars become infected in which the trifoliolate leaves develop mosaic followed by yellowing of the plant and drying of the veins, petioles, and stems. These plants frequently die. The best form of control is to use resistant cultivars and isolate bean crops from peanut crops. (Disease Caused by Viruses)

PEANUT STUNT (PSV)

‘‘‘Peanut Stunt (PSV) ‘‘‘ This disease is characterized by mosaic, drying of plant tissues, rugged leaf edges, deformation, and stunting. Pods rarely develop and if they do they are small and malformed with only a few seeds being produced. There are no control measures available at this time on the disease. (Disease Caused by Viruses)

PHOSPHORUS DEFICIENCY

‘‘‘Phosphorus Deficiency ‘‘‘ Beans do not require large amounts of phosphorus and do not normally show phosphorus deficiency unless soil-test phosphorus is low. Phosphorus deficiency symptoms typically occur as slow growth, small, dark green leaves, and older leaves may turn yellow and prematurely senesce. Flowering and maturation may be delayed. Phosphorus deficiency promotes flower abortions and results in reduced pod numbers and low seed yields. Where low soil test indicates phosphorus deficiency, band application of phosphorus fertilizer is more effective. (Noninfectious Disorder -- Nutritional Disorder)

PHYLLOSTICTA LEAF SPOT (PHYLLOSTICTA PHASEOLINA)

‘‘‘Phyllosticta Leaf Spot (Phyllosticta phaseolina) ‘‘‘ This disease is characterized by lesions that develop on the leaves that have a light-colored, dry center and are surrounded by a reddish brown margin. The lesions are also small, angular, water-soaked spots that may group together and enlarge to 7-10 mm in diameter. The centers of old lesions may fall out giving the leaf a shot-holed and tattered appearance. The best form of control is to apply copper or carbamate fungicides. (Fungal Disease of Leaf and Stem)

PHYMATOTRICHUM ROOT ROT (PHYMATOTRICHUM OMNIVORUM)

‘‘‘Phymatotrichum Root Rot (Phymatotrichum omnivorum) ‘‘‘ This disease is characterized by slight yellowing or bronzing of the leaves followed by sudden wilting when plants begin to flower. Plants usually die within a few days after wilting, often in a circular pattern, as the fungus grows radially from dying plants. There are no control measures available other than using good cultural practices. (Fungal Disease of Roots)

PINK POD ROT (TRICHOTHECIUM ROSEUM)

‘‘‘Pink Pod Rot (Trichothecium roseum) ‘‘‘ The disease is characterized by a powdery mold that is white and develops in the center of the lesions, then spreads outwards, and finally turns pink. In maturing pods, the diseased seeds become yellowish brown to chocolate brown and may be shriveled and covered with powdery pink mold. There is no control for the disease because little is known about it. (Fungal Disease of Leaf and Stem)

POTASSIUM DEFICIENCY

‘‘‘Potassium Deficiency ‘‘‘ Beans use relatively small amounts of potassium and symptoms of deficiency are not commonly observed unless soil test potassium is low. Some cultivars are very efficient in utilizing small amounts of soil potassium. Deficiency symptoms usually appear as firing or scorching of the leaf margins progressing toward the center and base of the leaf. Plants have weak stems and poor root growth and may collapse or lodge easily. Deficiencies are best prevented by application of potassium chloride or potassium sulfate according to soil test. (Noninfectious Disorder -- Nutritional Disorder)

POWDERY MILDEW (ERYSIPHE POLYGONI)

‘‘‘Powdery Mildew (Erysiphe polygoni) ‘‘‘ This disease is characterized by spots that are slightly darkened, about 10 mm in diameter, and develop on the upper surfaces of leaves. These areas become covered by a circular growth of white, superficial, powdery mycelium which may spread on the entire leaf and plant causing the plant to become distorted and yellow. The best form of control is the use of resistant cultivars. (Fungal Disease of Leaf and Stem)

PYTHIUM BLIGHT (PYTHIUM SPP)

‘‘‘Pythium Blight (Pythium spp.) ‘‘‘ This disease is characterized by water-soaked, brown tissue that initially occurs at a lower node and spreads rapidly up and down the stem. The infected tissues are soft and slimy. A white, woven mycelium often grows over infected tissue under humid conditions. The disease can also spread to the leaves and pods. The best form of control is to use resistant cultivars and rotate the crop with cereals or corn. (Fungal Disease of Leaf and Stem)

PYTHIUM DISEASES (PYTHIUM SPP)

‘‘‘Pythium Diseases (Pythium spp.) ‘‘‘ This disease is characterized by plants that show a lesion, initially water-soaked but becoming dry, extending from the roots up the hypocotyl and sometimes reaching the growing point. This disease often affects seeds or seedlings which may become mushy and discolored, fail to emerge, or wilt and die within the first few weeks of growth. There are only a few resistant varieties available and should be used. There are no other control measures for the disease. (Fungal Disease of Roots)

RED NODE

‘‘‘Red Node: ‘‘‘ This disease is characterized by a reddening of nodes of the stem and a cushion-like swelling at the base of leaves and leaflets. These symptoms may also be accompanied by drying and reddening of veins of primary and trifoliolate leaves. There are no control measures available because of the minor importance of the disease. (Disease Caused by Viruses)

RHIZOCTONIA ROOT ROT (THANATEPHORUS CUCUMERIS)

‘‘‘Rhizoctonia Root Rot (Thanatephorus cucumeris) ‘‘‘ This disease is characterized by small, elongated, sunken, reddish brown lesions that appear on hypocotyls and roots in the early development of the disease. As these lesions grow and become more sunken, they become cankerous, and the red color may take over until the cankers are old. These cankers may girdle the hypocotyls if they group together which may result in preemergence or postemergence damping-off. The best form of control is to apply a heavy application of fungicides as a seed treatment of soil drench. (Fungal Disease of Roots)

ROOT-KNOT NEMATODES (MELOIDOGYNE SPP)

‘‘‘Root-Knot Nematodes (Meloidogyne spp.) ‘‘‘ This disease is characterized by yellow, stunted, dry, or wilted plants especially during periods of moisture stress and high temperature. Galls or knots also develop on the roots and hypocotyls of infected plants. The best form of control is to use resistant cultivars where available. (Disease Caused by Nematodes)

RUST (UROMYCES APPENDICULATUS)

‘‘‘Rust (Uromyces appendiculatus) ‘‘‘ This disease is characterized by reddish brown, circular pustules on leaves or pods, which rupture the epidermis to produce abundant, powdery urediniospores. The best form of control is to use resistant cultivars where available. Not all cultivars are resistant to all forms of rust disease. (Fungal Disease of Leaf and Stem)

SCAB (ELSINOE DOLICHI AND PHASEOLI)

‘‘‘Scab (Elsinoe dolichi and phaseoli) ‘‘‘ This disease is characterized by tan, red or brown raised, wart-like protrusions that can be up to 10 mm in diameter appearing on leaves, stems, or pods. Leaf spots occur along the veins on either the upper or lower leaf surfaces, and develop slightly raised margins and turn yellow. The best form of control is to rotate with nonhost crops and treat the seed with chemicals. (Fungal Disease of Leaf and Stem)

SOUTHERN BEAN MOSAIC (SBMV)

‘‘‘Southern Bean Mosaic (SBMV) ‘‘‘ This disease is characterized by dark green, irregularly shaped, water-soaked, blotched areas on green-podded types and as greenish yellow areas on yellow-podded types. Pods may also become deformed resulting in poor seed set and reduced seed size. The best form of control is to use resistant varieties and plant virus-free seed. (Disease Caused by Viruses)

SOUTHERN BLIGHT (SCLEROTIUM ROLFSII)

‘‘‘Southern Blight (Sclerotium rolfsii) ‘‘‘ This disease is characterized by a slight yellowing of the lower leaves, water-soaking and slight darkening of the stem just below the soil line, followed by a yellowing of upper leaves and leaf drop. The fungus grows downward in the stem and roots, destroying the cortex. The best form of control is to use resistant cultivars. (Fungal Disease of Roots)

SOYBEAN RUST (PHAKOPSORA PACHYRHIZI)

‘‘‘Soybean Rust (Phakopsora pachyrhizi) ‘‘‘ This disease is characterized by yellow leaf spots that develop into small, angular, tan to reddish brown or purple leaf lesions that may only be 0.2-4.0 mm in diameter, within a week after infection. There are no control measures available because of the minor importance of the disease. (Fungal Disease of Leaf and Stem)

STEM ROT (SCLEROTIUM ROLFSII)

‘‘‘Stem Rot (Sclerotium rolfsii) ‘‘‘ This disease is characterized by wilting shortly after the plant has emerged from the soil which causes the plant to die. Plants that are established that become infected develop small lesions that are scattered on the hypocotyl and fibrous roots. Hypocotyl and stem lesions may be superficial, tan lesions or sunken, gray to black cankers. There are no measures of control for the disease because of its minor importance. (Fungal Disease of Leaf and Stem)

STIPPLE STREAK

‘‘‘Stipple Streak: ‘‘‘ This disease is characterized by reddish, dark brown, or black spots that are scattered and appear as streaks or bands on stems, petioles, and veins. The veins may also dry up leaving isolated patches differing in size and shape on the leaves. There are no control measures available for the disease. (Disease Caused by Viruses)

SULFUR DEFICIENCY

‘‘‘Sulfur Deficiency ‘‘‘ Sulfur deficiency has rarely been observed in beans, but may occur in highly leached acid soils of low organic matter. The symptoms appear as yellowing of the new leaves accompanied by reduced growth. Older leaves may be chlorotic in severe cases. Many sulfur-containing fertilizers are effective in preventing or correcting sulfur deficiency. (Noninfectious Disorder -- Nutritional Disorder)

TEMPERATURE STRESS

‘‘‘Temperature Stress: ‘‘‘ Plants that are exposed to low temperatures may produce chilling or frost damage, that appears as dark, water-soaked areas on wilted leaves or plants. If these low temperatures persist for an extended period of time, they may cause the plant to become stunted. High temperatures may cause flowers to abort, increase the rate of evapotranspiration causing leaf wilting or drying if there is an insufficient supply of soil moisture or if root growth is limited due to root rot, mechanical damage, or soil compaction. (Noninfectious Disease --Environment)

WEB BLIGHT (RHIZOCTONIA SOLANI)

‘‘‘Web Blight (Rhizoctonia solani) ‘‘‘ This disease is characterized by small, dry spots on the leaves that are 5-10 mm in diameter with brown centers and olive green margins, originating from sclerotia. Infections caused by basidiospores appear as distinct, small, dry, circular lesions 2-3 mm in diameter that are light brown or brick red with a lighter center. Symptoms on pods are similar to those produced on foliage by sclerotia or basidiospores. The best form of control is to apply chemical sprays with benomyl, carbendazim, and captafol and rotate with nonhost crops, such as cereals and corn. (Fungal Disease of Leaf and Stem)

WHITE LEAF SPOT (PSEUDOCERCOSPORELLA ALBIDA)

‘‘‘White Leaf Spot (Pseudocercosporella albida) ‘‘‘ This disease is characterized by spots that develop on the lower leaf surface and appear as white, angular areas that are 2-5 mm in diameter and found only on the veins. These spots may become slightly gray with age and are pale green to yellow on the opposite, upper leaf surface. The best form of control is to apply benomyl sprays and use resistant cultivars where available. (Fungal Disease of Leaf and Stem)

WHITE MOLD (SCLEROTINIA SCLEROTIORUM)

‘‘‘White Mold (Sclerotinia sclerotiorum) ‘‘‘ This disease is characterized by Infected flowers may develop a white, cottony appearance as mycelium grows on the surface. Lesions on pods, leaves, branches, and stems are initially small, circular, dark green, and water-soaked but rapidly increase in size, become slimy, and may eventually encompass and kill the entire organ. The best form of control is to use resistant cultivars where available, apply a fungicide spray, such as benomyl, during the flowering period, and rotate the crop with nonhost crops, such as cereals and corn. (Fungal Disease of Leaf and Stem)

WILDFIRE (PSEUDOMONAS SYRINGAE PV TABACI)

‘‘‘Wildfire (Pseudomonas syringae pv tabaci) ‘‘‘ This disease is characterized by dry, circular or angular lesions bordered by a yellow halo on infected leaves. There are no control measures available because little is known about the disease. (Disease Caused by Bacteria)

WITCHES'-BROOM

‘‘‘Witches'-Broom: ‘‘‘ This disease is characterized by plants becoming yellow, leaflets become smaller, shoot proliferation, and phyllody of floral organs. (Disease Caused by Mycoplasmalike)

ZINC DEFICIENCY

‘‘‘Zinc Deficiency ‘‘‘ Beans are among the crops most sensitive to zinc deficiency. Symptoms are frequently observed in beans grown in high pH soils of low zinc content. Yield reductions and delayed maturity may occur without accompanying symptoms. Low soil organic matter, cold soil temperatures, high nitrogen and phosphorus levels, poor root growth, and compaction can all induce deficiencies. Deficient plants develop dwarfed or deformed leaves with a mottled interveinal chlorosis. Chlorosis progresses to necrosis as severity increases. Plants may be stunted with shortened internodes. Delayed maturity is a frequent result of zinc deficiency. Zinc deficiency can be prevented by soil application of water soluble zinc sources such as zinc sulfate. Zinc EDTA is also effective, but costs significantly more. Insoluble zinc sources such as zinc oxide in granular form are ineffective. Band applications of 1-5 lbs Zn/acre are most effective. Banding of nitrogen and zinc together improves zinc uptake efficiency. Broadcast applications can also be used, but higher rates of 5-10 lbs Zn/acre are normally required for high pH soils. These rates may be effective for several years. Foliar application of soluble zinc fertilizers is also effective. A 0.5 to 1% zinc sulfate solution applied with a surfactant in enough water to wet foliage is an effective treatment. Repeated applications at 7-14 day intervals may be necessary. (Noninfectious Disorder -- Nutritional Disorder)