David B. Langston's Images
Title: Associate ProfessorOrganization: University of Georgia
Unit: Plant Pathology
Country: United States
| 117 Images of 71 Subjects | View Subject List | View Image Details | View Thumbnails |
| Image | Subject Name | Scientific Name | Description |
|---|---|---|---|
| 5077053 | Phytophthora blight | Phytophthora capsici | Brown, sunken, irregular shaped splotches with dark centers. Whitish mold may be observed when fungus is active. Splotches eventually begin to rot, especially during shipment. Unlike fruit blotch lesions, these lesions are soft. |
| 5077064 | bacterial fruit blotch | Acidovorax citrulli | Green water soaked splotch or lesion. Splotch may be small or cover the majority of the fruit. Splotch remains firm. |
| 5076090 | Alternaria leaf blight | Alternaria cucumerina | Brown to black spots with concentric rings observed within the spot. A yellow halo often occurs around a spot or group of spots. |
| 5077014 | paraquat | Paraquat herbicide injury on squash; Off target drift. Small, round white spots that appear burned. New leaves will be free of injury, but fruit are unmarketable. | |
| 5077060 | 2,4-D | 2,4-D type herbicide injury; Distorted leaves with characteristic "squiggly" mid rib in leaf. Leaves may drop. Could be confused with broadmite injury. | |
| 5077067 | 2,4-D | 2,4-D Herbicide Injury on Eggplant; Leaf is distorted and elongated. May or may not grow out of this injury. | |
| 5077050 | glyphosate | Glyphosate herbicide injury on tomato; Characteristic yellowing in the bud area. Very small amounts can cause injury on tomatoes. Higher concentrations will kill plant. | |
| 5077022 | edema | Edema on Cabbage; Sudden drop in temperatures and high soil moisture will cause leaf cells to rupture causing a wart-like appearance. New growth will not be affected unless conditions repeat. | |
| 5076093 | Pythium diseases | Pythium spp. | Pythium cottony leak on cucumber fruit. White, cotton like mass that may cover the entire fruit. Jelly or liquid may ooze from within the fruit. |
| 5076084 | chemicals | Chlorothalonil burn. Light green, white or burned appearance that is associated with this fungicide in the latter stages of watermelon development. | |
| 5077012 | gummy stem blight (vine decline) | Didymella bryoniae | Gummy Stem Blight on Watermelon (Didymella bryoniae); Stems show dark, water-soaked lesions often containing black, "pimple-like" fruiting structures. |
| 5077003 | powdery mildews | Comparison of Downy mildew and Powdery mildew on squash. Downy mildew: yellow spot on top and dark mold on bottom of leaf. Lesions can appear angular. Powdery mildew: noticeable white, moldy growth | |
| 5076087 | nutrient excess or toxicity (general) | Manganese Toxicity on Cantaloupe; Undersides of leaves have water-soaked areas with small, necrotic, raised areas in the center of the water-soaked area. Bronzed, chlorotic areas on the upper leaf surface. Symptoms occur in patches in fields that have low pH. This allows Mn to achieve toxic levels. | |
| 5076086 | herbicides (general) | Dinitroanaline Herbicide Injury on Watermelon Often occurs when applied preceding a heavy rainfall. Symptoms include swelling and splitting of the lower stem area. Wilting and plant death occur later in the season when high temperatures and heavy fruit load stress the plant. | |
| 5076100 | Fusarium wilts, blights, rots and damping-off | Fusarium spp. | White fungal growth on outside of fruit that may be pinkish in spots. |
| 5076085 | watermelon | Citrullus lanatus var. lanatus | Slightly raised, corky rings appearing in clusters on the surface of the fruit. No decay is associated with this unexplained disorder. |
| 5076070 | Botrytis leaf blight | Botrytis squamosa | Lesions appear as small, sunken, light tan areas surrounded by pale green tissue or "ghost halos". |
| 5076061 | cucurbits | Fruit spllits caused by combinations of low temperature and slow to fast growth due to changing environmental conditions and increased nitrogen application. Split starts small, getting progressively larger as fruit size increases. | |
| 5076063 | ozone | often appearing in the crown leaves when ozone levels build up to high concentrations during hot, humid conditions. Symptoms include a white or silver appearance on the top surface of leaves while the bottom surface is unaffected. | |
| 5076065 | watermelon | Citrullus lanatus var. lanatus | Physiological problem not associated with a disease. Small, brown lesions appear across a seam. Lesion is usually only as deep as the outer rind, but may allow introduction of other secondary fungi. |
| 5076067 | Fusarium wilts, blights, rots and damping-off | Fusarium spp. | Symptoms resemble nutrient deficiency or water stress. Basal plate will detach when onions are pulled. Off-white to orange growth can be seen on or around the basal plate. |
| 5076072 | bean anthracnose | Colletotrichum lindemuthianum | Large, brick red to brown, irregular shaped splotches on pods. Small, thin lesions of the same color can be seen on stems. Causes irregular seed development. |
| 5076073 | charcoal rot | Macrophomina phaseolina | Brown to tan lesion, covering the entire lower stem and girdling the plant. Black "pimple-like" structures observed in the lesion area. |
| 5076074 | dry bean rust | Uromyces appendiculatus | Small, red to brown spots that coalesce, eventually covering a large portion of the leaf. Plant may defoliate. |
| 5077011 | cucurbits | Misshapen fruit. Incomplete seed development can be observed when sliced open. | |
| 5077015 | cucurbits | lower stem area splits. Condition may be caused by combinations of low temperatures and slow to fast growth due to changing environmental conditions. | |
| 5077023 | cabbage | Brassica oleracea var. capitata | Internal browning of leaf tissue. Caused by a combination of low available soil calcium, inadequate root mass, extreme wet or dry soil conditions, and root pruning. |
| 5077055 | Cercospora leaf spot | Cercospora capsici | Black, circular spot with tan to white center. Spot may fall out leaving shot hole appearance. |
| 5076064 | anthracnose | Colletotrichum orbiculare | Brown to black, sunken lesions with concentric rings within the lesion. Begins as small spots that enlarge. A pink spore mass can often be observed on the surface of the lesion. |
| 5076099 | sandblasting | Leaf has burned appearance with interveinal chlorosis turning white. Area will desiccate and crumble. | |
| 5076091 | anthracnose | Colletotrichum orbiculare | Anthracnose on Watermelon (Colletotrichum orbiculare); Brown, irregular shaped lesion. Center of lesion will "split" in later development leaving a "shot hole" appearance. |
| 5076075 | Fusarium wilt | Fusarium oxysporum f.sp. niveum | Fusarium Wilt on Watermelon (Fusarium oxysporum f.sp. niveum) Portions of individual runners will wilt and die. Generally does not affect the entire plant at once. Whole plants eventually die. |
| 5076076 | Pythium diseases | Pythium spp. | Damping Off on Snap Bean (Pythium and Rhizoctonia) Collapse of the lower stem area. Caused by Pythium and Rhizoctonia. |
| 5077043 | powdery mildew | Podosphaera fuliginea | Powdery Mildew on Watermelon (Podosphaera xanthii syn. Sphaerotheca fuliginea) White, moldy growth. May appear on top or bottom of leaf. Could be confused with downy mildew in early stages. |
| 5077032 | downy mildew | Pseudoperonospora cubensis | Downy Mildew on Watermelon (Pseudoperonospora cubensis) Small, dark lesions that generally cover the leaf. Severely infected leaves will curl up on themselves. |
| 5077002 | anthracnose | Colletotrichum orbiculare | Anthracnose on Watermelon; (Colletotrichum orbiculare); Elongated lesion on stem. May have white center with tan or brown outline. May be able to see "setae" that are black, hair-like structures using a 20X hand lens. |
| 5077029 | downy mildew | Peronospora parasitica | Downy Mildew on Mustard (Peronospora parasitica) Yellow spots on top and whitish mold on bottom of leaf. Infection usually begins on bottom leaves. |
| 5077021 | gummy stem blight (vine decline) | Didymella bryoniae | Gummy Stem Blight on Watermelon (Didymella bryoniae); Brown to black lesions that sometimes contain concentric rings. Black "pycnidia" can be observed with hand lens. Lesions appear water- soaked or ashy. |
| 5077068 | Alternaria blight | Alternaria dauci | Infection begins as small, round spots with concentric rings within the lesion. Lesions can also be on petioles. Lesions enlarge and grow together causing a burned appearance. |
| 5077069 | carrot leaf blight | Cercospora carotae | Small, irregular, black to purplish colored spots. Spots may coalesce to cover the entire leaf. |
| 5077070 | Sclerotinia rot | Sclerotinia sclerotiorum | Grayish, white mold forms at the base of stem. Black "raisin" like structures appear as disease progresses. Can extend underground to the root.o |
| 5077071 | southern blight | Sclerotium rolfsii | Lower stem collapses. White mycelial growth and small tan to brown, round sclerotia can be observed. |
| 5077072 | Pythium diseases | Pythium spp. | Attacks growing point of the root causing a split. Carrot will not form normally. |
| 5077073 | southern blight | Sclerotium rolfsii | Fungus causes soil to adhere to the carrot root. |
| 5077074 | pink root of onion | Phoma terrestris | Severely infected plants appear to have a nutrient deficiency or water stress. Roots will range in color from light to deep pink. Can cause roots to become desiccated and shrivel up. Bulbs will be stunted. |
| 5077075 | root-knot nematode | Meloidogyne incognita | Galls or nodules associated with the root system caused by root-knot nematodes. May be small or large. |
| 5077076 | whiteflies | Symptom is white or silver coloring on leaves. Usually covers the entire leaf. Caused by whitefly feeding. | |
| 5077077 | bacterial spot | Xanthomonas vesicatoria | Dark brown irregular shaped splotches usually surrounded by chlorosis. May have greasy appearance. Bacteria from leaf will also splash onto fruit. |
| 5077030 | Alternaria black molds / stem cankers | Alternaria spp. | Black or brown spot. Concentric rings observed within spot. A yellow halo is often present around a spot or group of spots. Spot will sometimes drop out |
| 5077031 | Alternaria black molds / stem cankers | Alternaria spp. | Black or brown spot. Concentric rings observed within the spot. A yellow halo often occurs around a spot or group of spots. |
| 5077051 | anthracnose | Colletotrichum spp. | Sunken lesions that start small and enlarge with time. Salmon colored spore mass observed when fungus is active. |
| 5077052 | Phytophthora blight | Phytophthora capsici | Brown or black area observed on the upper stem or crown area. Whitish mold observed on fruit when fungus is active. Entire plant wil die.powerpo |
| 5077056 | Cucumber Mosaic Virus | Cucumovirus CMV | Chlorosis and puckering of leaf. Fruit symptom could be confused with Blossom End Rot.la |
| 5077057 | Tomato Spotted Wilt Virus | Tospovirus TSWV | Plant is dwarfed and stunted. Leaves are reduced in size and distorted. Faint rings can sometimes be observed on leaves. |
| 5077058 | Tomato Spotted Wilt Virus | Tospovirus TSWV | Small, irregular fruit with dark splotches. Fruit will not be marketable. |
| 5077059 | hail | Hole in fruit has characteristic "C" shape. Size of hole depends on the size of the hail and developmental stage of the fruit. (Below) | |
| 5077061 | broad mite | Polyphagotarsonemus latus | Extremely small. 1/3 the size of a spidermite. Eggs are round to oval in shape and are covered with characteristic white spots. Female will sometimes carry the male around on her back legs. |
| 5077062 | blossom end rot | Blackened or rotten on the blossom end of the fruit. Caused by calcium deficiency and is a problem in all fruiting vegetables. Necrotic areas may appear on any part of the fruit and not just the blossom end. Secondary infections of fungi may grow on the affected areas. | |
| 5077063 | southern blight | Sclerotium rolfsii | Rotting of lower stem resulting in total collapse of the plant. Small orange and white sclerotia (round fruiting bodies) can sometimes be observed at the soil line in later stages.=org |
| 5077065 | Phytophthora blight | Phytophthora capsici | Large area begins to rot. Fruit will often fall away from the calyx. Whitish mold may be present when conditions permit. |
| 5077066 | fruit rot | Phomopsis vexans | Brown to black lesion on fruit. Pycnidia or "pimple-like structures" can be observed with a hand lens when fungus is active. Pycnidia often form in concentric rings. |
| 5077054 | bacterial spot | Xanthomonas vesicatoria | Dark brown, irregular shaped splotches with chlorosis surrounding lesions. Splotches may have greasy appearance. Affected leaves will drop in latter stages when fungus is active. Entire plant may die. |
| 5077013 | herbicides (general) | Soft, mushy, spots on the fruit. May not show up until the fruit has been in storage or on display. | |
| 5077016 | downy mildew | Peronospora parasitica | Yellow spots on top of leaf, whitish mold on the bottom of the leaf. Lesions on undersides of leaf are often restricted by veins. |
| 5077017 | black rot of crucifers | Xanthomonas campestris pv. campestris | Initial infection begins as yellow "V" shaped spot on edge of leaf. Black veins eventually appear as infection spreads. |
| 5077018 | Sclerotinia rot | Sclerotinia sclerotiorum | Entire head begins to collapse with white fungal growth observed. Black, raisin-like structures observed in latter stages of development.powerpo |
| 5077019 | Cabbage Leaf Curl Virus | Geminivirus CaLCuV | Bud appears distorted and puckered. Growing point ceases development. May or may not return to normal growth. |
| 5077020 | bacterial black stalk | Erwinia spp. | stem will collapse at base of head. Has strong putrid odor in latter stages. Plant and head appear wilted in initial stages. |
| 5077004 | Phytophthora blight | Phytophthora capsici | Constriction at base of stem. Plant collapses with crown area turning necrotic. Dead plant looks like a "Dead Spider" when it collapses. |
| 5077005 | Phytophthora blight | Phytophthora capsici | sometimes only affects the fruit with a whitish, pasty growth. Plant may not be affected. |
| 5077006 | Squash Mosaic Virus | Comovirus SqMV | Leaves appear with yellow and green mosaic pattern. Leaves may be puckered and distorted. |
| 5077007 | Squash Mosaic Virus | Comovirus SqMV | Fruit appears with yellow and green streaks, splotches and raised areas (blisters). |
| 5077008 | bacterial black stalk | Erwinia spp. | Lower stem area will break during high wind or stress. Brown to orange area observed in latter stages. Strong putrid odor. |
| 5077009 | bacterial brown spot of bean/canker of stone fruit, twig blight | Pseudomonas syringae pv. syringae | Tan, irregular angular spots. Spots may drop out leaving a shot hole appearance. Pseudomonas is worse during cool weather. |
| 5077010 | Choanephora fruit rot | Choanephora cucurbitarum | Gray to black "whisker" appearance on the fruit. Usually found on blossom end and is favored by high humidity. |
| 5077033 | white leaf spot | Cercospora brassicicola | Tan or brown spot. Center of spot may fall out. Concentric rings may be observed.ave-fla |
| 5077034 | white leaf spot | Cercospora brassicicola | Initial infection appears as tan or light brown spots. Spots soon coalesce and may drop out. Could be confused with spray burn. |
| 5077035 | Sclerotinia rot | Sclerotinia sclerotiorum | Grayish, white mold observed usually at base of plant. Black "raisin" like structures observed in latter stages of development. Plant will collapse in latter stages. |
| 5077036 | Turnip Mosaic Virus | Potyvirus TuMV | Interveinal chlorosis observed. Leaves will sometime appear puckered and distorted. |
| 5077037 | Turnip Mosaic Virus | Potyvirus TuMV | Interveinal chlorosis observed. Leaves will sometime appear puckered and distorted.e-fla |
| 5077038 | clomazone | Clomazone herbicide injury on collards; Off-target drift. Tissue turns yellow or white depending on concentration. | |
| 5077039 | herbicides (general) | Chlorimuron herbicide carryover on mustard; Plant germinates and emerges but is severly stunted. | |
| 5077040 | white leaf spot | Cercospora brassicicola | Def/Folex injury on turnip; Off-target drift. White desiccated spots. Burned area may fall out leaving a shot hole appearance. |
| 5077041 | Tomato Spotted Wilt Virus | Tospovirus TSWV | Concentric rings appear on fruit. Other symptoms include uneven ripening and brown splotches.ed. |
| 5077042 | Tomato Spotted Wilt Virus | Tospovirus TSWV | Plant is stunted and leaves may appear bronzed with many small lesions that may or may not contain a concentric ring pattern.¬ |
| 5077044 | bacterial spot | Xanthomonas vesicatoria | Black spots on fruit that may have white centers. |
| 5077045 | Southern bacterial wilt | Ralstonia solanacearum (except Race 3 Biovar 2) | Total collapse of the plant usually occurring when temperatures reach 90 degrees and above. Plant wilts while still green. (Below left) Bacteria will stream out of tissue taken from lower stem.mb=295 |
| 5077046 | Fusarium wilt | Fusarium oxysporum f.sp. lycopersici | General wilting of the plant. A characteristic yellow color observed in the top of the plant. |
| 5077047 | early blight | Alternaria solani | Spots can be brown or black with concentric rings observed within the spot. A yellow halo often occurs around a spot or group of spots. |
| 5077048 | Tomato Yellow Leaf Curl Virus | Begomovirus TYLCV | Bud area turns yellow and leaves are curled and reduced to give a "mouse-ear" appearance. Overall stunting of plant. |
| 5077049 | Tomato Yellow Leaf Curl Virus | Begomovirus TYLCV | Bud area turns yellow and leaves are curled and reduced to give a "mouse-ear" appearance. Overall stunting of plant. |
| 5077024 | club root of crucifers | Plasmodiophora brassicae | Knotted roots resemble root-knot nematode injury. Above ground symptoms are stunted, chlorotic, unthrifty plants due to reduced uptake of water and nutrients through roots. |
| 5077025 | frost and winter injury (general) | Cold stress on cabbage; Sudden drop in temperatures and other stresses will trigger anthocyanin production causing a "purpling" of the outer leaves. Plants will usually grow out of this condition as temperatures moderate. | |
| 5077026 | calcium deficiency | Calcium Deficiency in Cabbage; Exhibits characteristic "tip burn" at tips/edges of the leaf. Leaves are deformed and cabbage head will not form if supplemental calcium is not applied. Cupping of leaves is typical. | |
| 5077027 | herbicides (general) | Alachlor injury; Off-target drift. Bud area turns yellow with interveinal chlorosis. Bottom leaves will burn off. Plant will remain stunted during the growing season. | |
| 5077028 | herbicides (general) | Imazapic herbicide carryover; plant is stunted and exhibits purpling leaves which are often strapped. Plant forms multiple heads from auxiliary buds. | |
| 5076077 | Pythium diseases | Pythium spp. | White, fluffy mass on pods and stems causes a watery rot. Normally associated with hot temperatures and heavy rainfall. |
| 5076078 | Sclerotinia rot | Sclerotinia sclerotiorum | White, fluffy mycelia grow on surface and form black sclerotia. Tissue turns tannish or gray and is highly deteriorated. Looks like cottony leak (Pythium) but occurs during cool weather. |
| 5076079 | Southern corn leaf blight and stalk rot | Bipolaris maydis | Long, irregular shaped, tan to white lesions. Lesions will appear along the leaf vein.la |
| 5076080 | northern corn leaf blight | Exserohilum turcicum | Small, tan to brown, somewhat round spots. May completely cover the leaf.1162825 |
| 5076081 | puccinia rusts | Puccinia spp. | Small, slender, brown to black spots that run with the leaf vein. May cover the entire leaf. |
| 5076082 | corn smut | Ustilago zeae | Corn kernels are grossly enlarged and distorted with a white to grayish color. May cover the entire ear. |
| 5076083 | blossom end rot | Blackened or rotten appearance on the blossom end of the fruit. Caused by calcium deficiency and affects all fruiting vegetables. Secondary fungal infections may occur on the affected areas.la | |
| 5076062 | Fusarium wilt | Fusarium oxysporum f.sp. lycopersici | Characteristic darkening of the vascular system. This can be observed by cutting just under the outside tissue on the lower stem.spots. |
| 5076068 | purple blotch | Alternaria porri | Begins as a small water-soaked lesion with a white center. Lesions usually turn purple to brown in color and may show concentric rings within lesions. |
| 5076069 | sour skin of onion | Burkholderia cepacia | Symptoms usually visible only after onions are dug. Outer layer of scales often becomes darkened and almost orange. Decay of inner scales leads to a soft rot that has a sour, vinegar-like odor.tmb=295 |
| 5076066 | botrytis rot | Botrytis allii | First symptoms appear at soil line. Symptoms include watersoaked and sunken lesions. Decay continues down into and throughout the bulb. Gray, mycelial mat can often be found between the outer scales.5 |
| 5076092 | Rhizoctonia damping-off, blight and rot | Rhizoctonia solani | belly rot of cucumber; brown, irregular shaped lesions on the bottom of fruit. May have crusty appearance as lesions dry. |
| 5076088 | bacterial fruit blotch | Acidovorax citrulli | Brown or tan. "V" shaped water soaked lesion on the leaf. Many times this lesion is at the edge or tip of the leaf. |
| 5076089 | bacterial fruit blotch | Acidovorax citrulli | Brown or tan. "V" shaped water soaked lesion on the leaf. Many times this lesion is at the edge or tip of the leaf. (Below) Small, brown, sunken round spot. Netting does not extend into the lesion.295 |
| 5076071 | bacterial leaf streak and bulb rot | Pseudomonas viridiflava | Symptoms appear as water-soaked, dark green areas at the base of the onion leaves. Affected leaves tear off without much force. Disease occurs more during cool, wet periods during onion production. |
| 5077001 | powdery mildew | Podosphaera fuliginea | White, moldy growth. May appear on top or bottom of leaf. Could be confused with downy mildew. |
| 5076094 | nutrient deficiency | Interior portion of fruit does not develop leaving a hollow area that makes fruit unmarketable. Caused by a complex of calcium and boron deficiency in combination with insufficient water movement into the plant. | |
| 5076095 | anthracnose | Colletotrichum orbiculare | Brown or tan angularly shaped spot. Structures called "setae" which are black and hair-like can sometimes be observed with a hand lens. |
| 5076096 | Phytophthora blight | Phytophthora capsici | Initial infection has a sunken area on fruit. Whitish mold observed when fungus is active. May not manifest until fruit has been packed and shipped. |
| 5076097 | Cucumber Mosaic Virus | Cucumovirus CMV | Interveinal chlorosis observed. Leaves will sometimes look puckered and distorted.ve-fla |
| 5076098 | hail | Hole in leaf has characteristic "C" shape. Size of hole depends on the size of the hail. Typically ragged irregular holes. |
