Pacific Northwest Vegetable Extension Group

of Washington State University, Oregon State University, and University of Idaho

Photo Gallery of Vegetable Problems

Diseases, pests, and other problems common to many vegetables

In addiditon to the resources found here, the WSU Urban IPM Program’s Hortsense and Pestsense websites are designed for homeowner education and are used by County Extension Educators, Master Gardener Coordinators, Master Gardeners and Clinic Diagnosticians. Together, the two websites contain 1,050 fact sheets which provide up-to-date, research-based information on problem insects, diseases, and weeds and their management. The websites have been upgraded and the new versions are now available online. Additional features include a Hortsense image library and search, print and email options.

(Click on photo to enlarge)


Diseases


Disease: Clubroot of brassica vegetables
Pathogen: Plasmodiophora brassicae
Host crops: Broccoli, cabbage, cauliflower, brassicaceae (cruciferous) weeds, and radish.

Photo of below-ground symptoms of clubroot.
Below-ground symptoms of clubroot.
Photo Source: Lindsey du Toit

On-Line Resources:

Pacific Northwest Plant Disease Management Handbook: Cabbage and Cauliflower (Brassica sp.) – Clubroot

Clubroot of Crucifers. Vegetable MD Online.

Clubroot. Wikipedia.

Clubroot of vegetable brassicas – towards integrated control. New Zealand Institute for Crop & Food Research Ltd.

Clubroot of Crucifers. The Ohio State University Extension.

Managing Clubroot: Equipment Sanitation Guide. Canola Council of Canada

Top 10 tips from the 2013 International Clubroot Workshop. Canola Watch, Canola Council of Canada.




Disease: Damping-off/Seedling blight
Pathogen: Aphanomyces, Fusarium, Pythium, and Rhizoctonia species.
Host crops: Most vegetables are susceptible to damping-off/seedling blight including watermelon.

Photo of phthium root rot of watermelon Post-emergence damping-off of spinach seedlings. Note the wilted and dead seedlings in the center of the photos. Damped-off spinach seedlings washed in water to show root symptoms. Note the brown and blackened roots of damped-off seedlings compared to the white root of a healthy seedling.
Post-emergence damping-off of spinach seedlings. Note the wilted and dead seedlings in the center of the photos. Damped-off spinach seedlings washed in water to show root symptoms. Note the brown and blackened roots of damped-off seedlings compared to the white root of a healthy seedling.
Photo Source: Lindsey du Toit, Washington State University

On-Line Resources:

Pacific Northwest Plant Disease Management Handbook: Damping-off in Vegetable Seedlings

Pacific Northwest Plant Disease Management Handbook: Corn (Zea mays) – Seed Rot and Seedling Blight

Pacific Northwest Plant Disease Management Handbook: Watermelon (Citrullus lanatus) – Damping-off

Common Diseases: Damping-off. Washington State University Hortsense.
 




Disease: Verticillium wilt
Pathogen: Verticillium species, including V. albo-atrum, V. dahliae and V. longisporum, depending on the vegetable crop.
Host crops: Numerous vegetables including many brassica vegetables (but not broccoli), cucumber, eggplant, pepper, potato, pumpkin, radish, spinach, tomato, watermelon, etc.

Photo of verticillium wilt of spinach Photo of Verticillium wilt on potato
Symptoms of Verticillium wilt only develop after initiation of 'bolting' (reproductive growth), and start as interveinal chlorosis of the lower leaves that progresses to interveinal necrosis.
Photo Source: Lindsey du Toit Photo Source: G.Q. Pelter

On-Line Resources:

Pacific Northwest Plant Disease Management Handbook: Plants Resistant or Susceptible to Verticillium Wilt

Common Diseases: Verticillium wilt. Washington State University Hortsense.

Cucumber, Pumpkin, Squash: Verticillium wilt, Washington State University Hortsense

Verticillium Wilt in Spinach Seed Production

Pacific Northwest Plant Disease Management Handbook: Spinach (Spinacia oleracea) – Verticillium Wilt

Crop Profile for Spinach Seed in Washington

Pacific Northwest Plant Disease Management Handbook: Potato (Solanum tuberosum) – Verticillium Wilt {Potato Early Dying}

Potato: Verticillium wilt (Potato early dying), Washington State University Hortsense

Pacific Northwest Plant Disease Management Handbook: Tomato (Lycopersicon esculentum) – Wilts (Fusarium wilt, Verticillium wilt)

Tomato: Verticillium wilt, Washington State University Hortsense
 




Disease: White mold
Pathogen: Sclerotinia sclerotiorum
Host crops: Bean, various brassica vegetables, carrot, eggplant, lettuce, potato, tomato, etc.

Photo of white mold on green bean Photo of carrot white mold dieback Photo of  symptoms resulting from basal infection of the stem from sclerotinia of the fungus residing in the soil Photo of White mold on tomato
White mold infection of a bean plant. Dead and dying plants in a carrot seed crop infected with white mold. Symptoms resulting from basal infection of the lettuce stem from Sclerotinia inoculum in the soil. White mold infection of a tomato plant.
Photo Source: G.Q. Pelter Photo Source: Lindsey du Toit Photo Source: E. J. Sorensen
Photo of symptoms of white mold on caabbage
White mold symptoms on a cabbage head.
Photo Source: Lindsey du Toit

On-Line Resources:

Pacific Northwest Plant Disease Management Handbook: Bean, Snap (Phaseolus vulgaris) – White Mold {Sclerotinia Rot}

Bean: White mold (Sclerotinia rot). Washington State University Hortsense

Pacific Northwest Plant Disease Management Handbook: Cabbage and Cauliflower (Brassica sp.) – Sclerotinia Stem Rot and Watery Soft Rot

Pacific Northwest Plant Disease Management Handbook: Carrot (Daucus carota) Cottony Rot

Carrot: Cottony Rot (White Mold). Howard F. Schwartz and David H. Gent, Colorado State University

Pacific Northwest Plant Disease Management Handbook: Lettuce (Lactuca sativa) – Drop {Sclerotinia Rot}

UC Pest Management Guidelines: Lettuce: Lettuce Drop. UC IPM Online. University of California.

Diseases of lettuce ( Lactuca sativa ) in Arizona: Leaf drop. Extension Plant Pathology, The University of Arizona.

Evaluation of Products to Manage Sclerotinia Leaf Drop of Lettuce in 2003. The University of Arizona Cooperative Extension.

Pacific Northwest Plant Disease Management Handbook: Pepper (Capsicum sp.) – White Mold

Pacific Northwest Plant Disease Management Handbook: Potato (Solanum tuberosum) – White Mold {Sclerotinia Stem Rot}

Pacific Northwest Plant Disease Management Handbook: Tomato (Lycopersicon esculentum) – White Mold
 

Nematodes




Disease: Root knot
Pathogen: Meloidogyne species
Host crops: Numerous plant species including many vegetables such as carrot, coriander, onion, potato, etc.

Photo of Root knot nematode on carrot Photo of galls cause by root knot nematode Photo of coriander in field showing symptoms of root knot nematode damage Photo of coriander seedlings showing various degrees of dieback and root galling
  Galls caused by root knot nematode. Patches of stunted plants in a coriander seed crop caused by root knot nematode. Coriander seedlings showing various degrees of dieback and root galling from root knot nematode.
Photo Source: E. J. Sorensen Photo Source: Lindsey du Toit, Washington State University
Photo of root knot on potato Photo of root knot on potato
Symptoms of root knot on potato tubers
Photo Source: G.Q. Pelter

On-Line Resources:

Pacific Northwest Plant Disease Management Handbook: Carrot (Daucus carota) – Nematode, Root-knot

Carrot: Root-knot nematode, Washington State University Hortsense

Pacific Northwest Plant Disease Management Handbook: Nematodes

Major Emerging Problems with Minor Meloidogyne Species. By Axel A. Elling, Washington State University.

Pacific Northwest Plant Disease Management Handbook: Potato (Solanum tuberosum) – Nematode, Root-knot

Onion and Garlic: Nematodes, UC IPM Online, University of California

Root-knot nematode. APSnet
 


Insect/Mite Pests


Common names: Numerous aphids can infest vegetable crops, e.g., bean aphid, green peach aphid, melon aphid, and potato aphid.
Latin binomial: Numerous types of aphids including Aphis fabae (bean aphid), Myzus persicae (green peach aphid), Aphis gossypii (melon aphid), and Acrosiphum euphorbiae (potato aphid)
Host crops: In addition to cucumber, corn seed, melon, potato, tomato, eggplant and pepper, aphids can feed on many other vegetables including broccoli, cabbage, spinach, Swiss chard, squash, pumpkin, beet as well as many weed species including Brassicaceae (cruciferous) weeds.

Photo of green peach aphid nymph on leaf Photo of green peach aphid Photo of aphid damage on leaf
Green peach aphid may be found along the midrib on the underside of leaves of a host plant. Mature aphids are about 2 mm long (ca. 1/16 inch), egg-shaped, and the color of the wingless nymphs and adults ranges from pinkish yellow to yellowish green. There are usually multiple individuals in a single colony. The green peach aphid tends to overwinter in stone fruit trees. By late May to early June, individual aphids in a colony develop wings and fly to vegetable crops and a wide range of weeds. As the aphids disperse (June to August), they can transmit important viruses including potato leaf roll virus and potato virus Y. The easiest way to scout for aphid colonies is to search perimeter vegetable plants for copious amounts of sticky, glistening honeydew coating the upper surfaces of lower leaves of plants. Honeydew may contain numerous cast (shed) skins (white to gray) and a black sooty mold (fungus) that colonizes aphid honeydew.
Photo Source: Michael Bush, WSU Extension, Yakima, WA

On-Line Resources:

Biology and Management of Aphids in Organic Cucurbit Production Systems, Washington State University Extension and the Cooperative Extension System.

Pacific Northwest Insect Management Handbook: Vegetable crop pests-Aphid

Pacific Northwest Insect Management Handbook: Potato, Irish – Aphid

Pacific Northwest Insect Management Handbook: Pumpkin and squash – Aphid.

Common Insect & Mite: Aphids, Washington State University Hortsense.
 

Common name: Blister beetle
Latin binomial: Epicauta spp. including E. maculata
Host Crops: Blister beetles are typically considered beneficial insects as the larvae feed on grasshopper eggs, but they are occasional pests on crops such as alfalfa, beets, beans, clover, potatoes, other vegetable and field crops, and native plants.

Photo of blister beetle damage to potato Photo of blister beetle damage to potato Photo of blister beetle damage to potato Photo of blister beetle on potato
Blister beetles defoliated a short section of an outside row of a potato crop, but did a little damage beyond that. The potato crop was adjacent to rangeland that had a lot of grasshopper eggs on which blister beetle larvae feed.
Photo Source: Sally Hubbs
Close-up photo of blister beetle Close up photo of blister beetle
Adult blister beetle of the species Epicauta pruinosa, which is differentiated from adults of E. fabricii by the second antennal segment: shorter than the third segment on E. pruinosa but longer or equal to the third segment on E. fabricii. E. fabricii has a range south and east of Oregon, while E. pruinosa appears to be common in the Pacific Northwest and has a wider range. The two species produce different levels of cantharin, which is toxic and lethal to cattle.
Photo Source: OSU-HAREC Rondon’s lab (A. Murphy)

On-Line Resources:

Blister Beetles: Pest or Beneficial Predator?, Washington State University Extension Fact Sheet FS113E.

Blister Beetles: Coleptera: Meloidae Epicauta maculata, E. fabricii, E. puncticollis, Lytta nutalli. Modified from G. Bishop, et al. 1982. Management of Potato Insects in the Western States, Integrated Plant Protection Center of Oregon State University.

Blister Beetles, Identification & Management of Emerging Vegetable Problems in the Pacific Northwest. Pacific Northwest Vegetable Extension Group.

Pacific Northwest Insect Management Handbook. Chapter: Vegetables, Section: Table Beets (aphid to cucumber beetle)


Common name: Broad mites are tiny (0.2 mm-long adult females), oval, light yellow to amber or white or even green arachnids (so they have eight legs). Male adults are smaller. There are four life stages: egg, larva, nymph and adult. Eggs are colorless, translucent, elliptical, about 0.08 mm long, and covered with white tufts on the upper surface. Young broad mites have only three pairs of legs, are slow moving, and whitish in color. The quiescent stage is an immobile, engorged larva. Injury to broad mites can be difficult to diagnose because of how small the pests are and the locations where they feed on plants. Broad mites typically feed within growing meristems and require magnification to be seen.
Latin binomial: Polyphagotarsonemus latus (Arachnida: Acari: Tarsonemidae)
Host crops: Broad mites have a wide host range in tropical areas and commonly infect plants in greenhouses in temperate and subtropical areas. Hosts include many perennial and annual plant species, including ornamentals, citrus, grape, and vegetables such as bean, cucurbits, eggplant, tomato, pepper, potato, etc. Adults feed on the lower surface of leaves and on fruit.

Severe damage to pepper plants caused by broad mites. Severe damage to pepper plants caused by broad mites. Close-up image of broad mite eggs on pepper. Close-up image of tiny, white, broad mites on pepper fruit.
Severe damage to pepper plants caused by broad mites. Close-up image of broad mite eggs on pepper.Close-up image of broad mite eggs on pepper.   Close-up image of tiny, white, broad mites on pepper fruit.
Photo Source: Washington State University Puyallup Diagnostic Lab
Damage to pepper plants by broad mites. Damage to pepper plants by broad mites. Damage to pepper plants by broad mites.
Damage to pepper plants by broad mites.
Photo Source: Lou Almasi

Online Resources:

Broad Mites in Fruiting Vegetables, Penn State Extension, Plants and Pests, Vegetable, Small Fruit, and Mushroom Production News.

Broad Mite, Featured Creatures, Entomology & Nematology, FDACS/DPI, EDIS, University of Florida.

Broad mite is becoming an increasing problem, Dan Gilrein, Greenhouse Management Magazine.

Broad Mite, Entomology: Insects Associated With Vegetable Crops in Georgia: Solanaceous Crops, University of Georgia College of Agricultural and Environmental Sciences.

Broad mite: Not your typical Michigan mite, Michigan State University Extension News.


 

Common name: Brown marmorated stink bug (BMSB)
Latin binomial: Halyomorpha halys
Host crops: Very wide host range including Oregon berry, grape, tree fruits, hazelnuts, vegetables including pepper, corn, tomato, ornamentals, etc.

Three or four key characteristics are used to distinguish the brown marmorated stink bug (BMSB) from other stink bugs found in the Pacific Northwest: 1) white bands on the brown antennae, 2) bands on the dorsal (top) side of the peripheral margin of the abdomen, 3) smooth leading edge of the prothorax (shoulders), 4) ‘gem-encrusted’ prothorax just behind the head (on both the dorsal and ventral side). Three or four key characteristics are used to distinguish the brown marmorated stink bug (BMSB) from other stink bugs found in the Pacific Northwest: 1) white bands on the brown antennae, 2) bands on the dorsal (top) side of the peripheral margin of the abdomen, 3) smooth leading edge of the prothorax (shoulders), 4) ‘gem-encrusted’ prothorax just behind the head (on both the dorsal and ventral side). Three or four key characteristics are used to distinguish the brown marmorated stink bug (BMSB) from other stink bugs found in the Pacific Northwest: 1) white bands on the brown antennae, 2) bands on the dorsal (top) side of the peripheral margin of the abdomen, 3) smooth leading edge of the prothorax (shoulders), 4) ‘gem-encrusted’ prothorax just behind the head (on both the dorsal and ventral side). Three or four key characteristics are used to distinguish the brown marmorated stink bug (BMSB) from other stink bugs found in the Pacific Northwest: 1) white bands on the brown antennae, 2) bands on the dorsal (top) side of the peripheral margin of the abdomen, 3) smooth leading edge of the prothorax (shoulders), 4) ‘gem-encrusted’ prothorax just behind the head (on both the dorsal and ventral side).
Three or four key characteristics are used to distinguish the brown marmorated stink bug (BMSB) from other stink bugs found in the Pacific Northwest: 1) white bands on the brown antennae, 2) bands on the dorsal (top) side of the peripheral margin of the abdomen, 3) smooth leading edge of the prothorax (shoulders), 4) ‘gem-encrusted’ prothorax just behind the head (on both the dorsal and ventral side).
Photo Source: Lyndon Porter, USDA ARS
Photo of pepper showing symptoms from brown marmorated stink bug damage Photo of pepper showing symptoms from brown marmorated stink bug damage Photo of pepper showing symptoms from brown marmorated stink bug damage Photo of pepper showing symptoms from brown marmorated stink bug damage
       
Photo Source: Nik Wimann, Oregon State University
Photo of pepper showing symptoms from brown marmorated stink bug damage Photo of brown marmorated stink bug damage on tomato Photo of brown marmorated stink bug on corn Photo of brown marmorated stink bug Photo of brown marmorated stink bugs
      Adult Brown marmorated stink bug.  
Photo Source: Nik Wimann, Oregon State University Photo Source: Galen Dively, University of Maryland Photo Source: Tracy Leskey, USDA Photo Source: C. Hedstrom, Oregon State University
Photo of brown marmorated stink bug nymphs and eggs brown-marmorated-stink-bug-5 brown-marmorated-stink-bug-4 Closeup view of the ventral side of a brown marmorated stink bug. Marginal dorsal banding pattern of the abdomen of a brown marmorated stink bug.
Nymphs clustered around egg mass. BMSB eggs are typically blue-green in color when fresh.   Closeup view of the ventral side of a brown marmorated stink bug. Marginal dorsal banding pattern of the abdomen of a brown marmorated stink bug.
Photo Source: Nik Wimann, Oregon State University Photo Source: P Shearer, Oregon State University Photo Source: Lyndon Porter, USDA ARS  

On-Line Resources:

Brown Marmorated Stink Bug, Identification & Management of Emerging Vegetable Problems in the Pacific Northwest, Pacific Northwest Vegetable Extension Group.

Brown Marmorated Stink Bug in Oregon, Oregon State University

Brown Marmorated Stink Bug News. Information and updates for Oregon. Volume 1, Spring 2013. Oregon State University.

El Chinche Apestozo Marrón Marmolado en Vegetales (BMSB: Brown Marmorated Stink Bug) - Resumen de las recomendaciones para su control. Los autores son miembros del BMSB SCRI CAP (siglas en ingles): Equipo de Cultivo de Vegetales.

Integrated Pest Management for Brown Marmorated Stink Bug in Vegetables - A synopsis of what researchers have learned so far and management recommendations using an integrated approach. Authored by the BMSB SCRI CAP Vegetable Commodity Team.

Pest Alert: Brown Marmorated Stink Bug, A quick ID guide from the Oregon Department of Agriculture

Pest Watch: brown Marmorated Stink Bug, Washington State University Extension Fact Sheet FS0079E
 

Common name: Flea beetle
Latin binomial: Pictured is the western potato flea beetle, Epitrix subcrinita, but the tuber flea beetle, Epitrix tuberis, may also damage foliage.
Host crops: Eggplant, pepper, potato, and tomato.

Photo of potato flea beetle damage on potato foliage Photo of adult potato flea beetle Photo of adult potato flea beetle showing enlarged hind legs
Potato flea beetle damage on potato foliage appears as scallop-like scoops, rounded pits or shotholes originating from the underside of the potato leaf. The adult flea beetle is small (~1/16 inch long), oblong, and dark brown to bronze in color. The most distinctive feature of the flea beetle is the enlarged hind legs that provide the insect the ability to jump considerable distances when approached or disturbed.
Photo Source: Michael Bush, WSU Extension, Yakima, WA

On-Line Resources:

Potato Flea Beetles: Biology and Control. Washington State University Extension Bulletin 1198E.

Potato Flea Beetles. Coleoptera: Chrysomelidae Western Potato Flea Beetle Epitrix subcrinita, Tuber Flea Beetle Epitrix tuberis

Pacific Northwest Insect Management Handbook. Chapter: Irish Potatoes, Section: Flea Beetle to Grasshopper.

Vegetables: Potato: Potato flea beetles. Washington State University Hortsense.
 




Disease: Seedcorn maggot
Pathogen: Delia platura
Host Crops: Many vegetable crops including snap, kidney, and lima beans, onion, corn, turnip, pea, cabbage, and cucurbits. They cause the most damage in spring to newly emerging seedlings.

Photo of seedcorn maggot damage to onion Photo of seedcorn maggot larvae Photo of seedcorn maggot larvae Photo of seedcorn maggot fly on soil Photo of seedcorn maggot fly
Onion seedlings damaged by seed corn maggot larvae, with the larvae (white) and a pupa (brown) shown in relation to the size of a paper clip and damaged onion seedlings. Seedcorn maggot injury to bean leaves. Seedcorn maggot larvae. Seedcorn maggot fly on soil. Seedcorn maggot fly.
Photo Source: Lindsey du Toit, Washington State University Photo Source: Tim Waters, WSU Extension Educator for Benton and Franklin Counties


On-Line Resources:

Pacific Northwest Insect Management Handbook: Vegetable crop pests – Seedcorn maggot

Seed Corn Maggot. VegEdge, University of Minnesota

Seed Corn Maggot. UMass Amherst


 

Common name: Spider mites
Latin binomial: Tetranychus spp. including twospotted spider mite (Tetranychus urticae), strawberry spider mite (Tetranychus turkestani), and Pacific spider mite (Tetranychus pacificus)
Host crops: Wide host range, including many vegetables such as bean, carrot seed crops, potato, etc.

Photo of twospotted spider mite Eggs of the two-spotted spider mite, Tetranychus urticae. Photo of spider mite on carrot seed crop Photo ofspider mite on carrot seed crop
Twospotted spider mite on potato. Eggs of the two-spotted spider mite, Tetranychus urticae. Severe outbreak of spider mites in a carrot seed crop in central Washington.
Photo Source: Silvia Rondon, Oregon State University Photo Source: Lindsey du Toit, Washington State University

 

On-Line Resources:

Some Common Plant-Feeding Mites and Plant-Inhabiting Mite Predators in the Northwestern United States. PNW Insect Management Handbook.

Lima Bean – Spider Mites. PNW Insect Management Handbook.

Carrot seed – Twospotted spider mite. PNW Insect Management Handbook, Chapter: Vegetable Seed, Section: Carrot Seed.

Managing spider mites in gardens and landscapes. University of California Online Statewide Integrated Pest Management Program.


Common Name: Squash bug
Latin binomial: Anasa tristis
Host crops: Cucurbit vegetables (e.g. pumpkin and squash).

Photo of Squash bug nymphs Photo of adult adult squash bug Photo of squash bug showing long beak
Squash bug nymphs are wingless and range from 1/8 to 1/2 inch long with a grayish white body color. They often congregate in groups on the undersides of leaves. The adult squash bug has a flattened, elongate body, dark to grayish brown with a speckled pattern on the dorsum, and measure about 1/2 to 5/8 inch long. They may appear to have yellow to orange-striped borders on the abdomen. They release a foul odor when crushed. Squash bugs have a long “beak” that they insert into the vine or foliage, and feed by sucking sap from the plant. Yellow specking that later turns brown may appear on leaves where they feed. Severe feeding on young vines, or older vines during the heat of summer, can lead to plant wilingt distal to the point of feeding.
Photo Source: Michael Bush, WSU Extension, Yakima, WA

On-Line Resources:

Pacific Northwest Insect Management Handbook. Chapter: Vegetables, Section: Pumpkin and Squash, pt.2.

Vegetables: Cucumber, Pumpkin, Squash: Squash bug. Washington State University Hortsense.
 

Common name (of damaging stage): Western flower thrips
Latin binomial: Frankliniella occidentalis
Host crops: Host crops: Basil, Broccoli, Cabbage, Cauliflower, Cucumber, Onion, Potato, Pumpkin, Squash, Tomato, and Watermelon.

Photo of adult Western flower thrips Photo of immature Western flower thrips Photo of cosmetic damage to tomato fruit by thrips Photo of
Adult Western flower thrips are minute (less than 1/8 inch long) narrow-bodied insects that range from straw to dark yellowish-brown in color. Their four wings are very narrow and characterized by long fringed hairs. An immature Western flower thrip resembles the adult, but is smaller, wingless and translucent yellow in color. There may be multiple generations per year and thrips may invade vegetable fields when alternate flowering plants dry up in the summer or when an adjacent host crop is harvested. Thrips rasp (by puncturing individual surface cells and sucking cellular contents) the surface of flower and fruit tissues as they feed. Their feeding can weaken and deform flowers and reduce flower viability. The most visible damage is caused when they rasp the surface of the fruit in areas where two fruit come in contact or when a leave lies up against the fruit. This damage is cosmetic only and does not extend beneath the fruit skin. When given the opportunity, thrips will feed on the surface cells of cucumber fruit, leaving ghostly white stippling. This damage is cosmetic only, limited to the skin of the fruit. Early surface damage to the cucumber can appear as corky patches, negatively impacting the surface finish.
Photo Source: Michael Bush, WSU Extension, Yakima, WA

On-Line Resources:

Western Flower Thrips Thysanoptera: Thripidae Frankiniella occidentalis.

Pacific Northwest Insect Management Handbook. Chapter: Vegetables, Section: Broccoli, Cabbage, Other Crucifers.

Pacific Northwest Insect Management Handbook. Chapter: Vegetables, Section: Cucumber (garden symphylan to wireworm).

Vegetables: Bean: Thrips. Washington State University Hortsense.

Vegetables: Broccoli, Cole crops: Thrips. Washington State University Hortsense.
 

Common name: Whitefly
Latin binomial: Pictured in these photos is the greenhouse whitefly (Trialeurodes vaporariorum), but there are multiple species of whitefly that can plague vegetable crops.
Host crops: Eggplant, pepper, potato, tomato, and other crops. Whiteflies are more frequently a problem in greenhouse (transplants) than in field situations in the Pacific Northwest region of the USA.

Photo of adult whitefly Photo of immature whiteflies Photo of immature whitefly (nymph) Photo ofwhitefly egg attached to underside of leaf
Whiteflies resemble very small white moths. Whiteflies measure <1/8 inch (2 mm) in length. The adults tend to fly away as field scouts approach infested plants. Immature whiteflies resemble small, translucent scales found on the undersides of infested leaves. Immature whiteflies (nymphs) are very small and difficult to see without a hand lens. Whiteflies feed on plant sap. Large populations can cause leaves to yellow and prematurely drop from plants. Whiteflies excrete sticky honeydew that will cover leaves and become colonized by black sooty mold. A whitefly egg (white to brown in color) attached to the underside of a leaf. The egg is <1/16 inch (<1 mm) long.
Photo Source: Michael Bush, WSU Extension, Yakima, WA

 

On-Line Resources:

Greenhouse Whitefly: Biology and Control. Extension Bulletin 1349, Washington State University.

Pacific Northwest Insect Management Handbook. Chapter Irish Potatoes, Section: Tuberworm to Wireworm.


Common name (of damaging stage): Wireworm (adults are called click beetles or snapping beetles)
Latin binomial: Ctenicera spp. and Limonius spp. Several kinds of wireworms are in the Pacific Northwest. Wireworms causing the most damage in irrigated areas are the Pacific Coast wireworm (Limonius canus), the sugar beet wireworm (L. californicus), the western field wireworm (L. infuscatus), and the Columbia Basin wireworm (L. subauratus). The Pacific Coast and sugar beet wireworms are the most common. Where annual rainfall is <15 inches, the Great Basin wireworm (Ctenicera pruinina) may be a problem, especially when irrigated crops are grown on sagebrush or dry wheat land. This species usually disappears after a few years of irrigation, but may be replaced by Limonius spp. which are favored by moist conditions. West of the Cascades, other wireworm species are pests, including Agriotes spp.
Host crops: All crops are susceptible to wireworm, but this pest is most destructive on beans, carrot, corn, grain, onion, potatoes, spinach seed crops, and other annual crops in the PNW.

Photo of wireworm damage to onion bulb Photo of wireworms in soil around onion roots Photo of wirwirm in soil near onion roots Photo of field of onions showing wireworm damamge closeup of wireworm
         
Photo Source: Tim Waters, WSU Extension Educator Photo Source: Gary Pelter, WSU Extension Educator Emeritus Photo Source: Tim Waters,
WSU Extension Educator
Photo Source: Lindsey du Toit, Washington State University
Wireworms feeding on an onion plant in a bunching onion (CFC = cepa fisutlosum cross) seed crop. Photo of carrot showing wireworm and symptoms of wireworm damage Title Title A click beetle of the species Agriotes obscurus, the larvae of which are wireworms.
Wireworms feeding on an onion plant in a bunching onion (CFC = cepa fistulosum cross) seed crop. Damage to a carrot root from wireworms. A wireworm (click beetle larva). A wireworm feeding on plant roots. A click beetle of the species Agriotes obscurus, the larvae of which are wireworms.
Photo Source: Lindsey du Toit, Washington State University Photo Source: Doug Young, Professor Emeritus of Washington State University Photo Source: Oregon State University-Irrigated Agricultural Entomology Program (Silvia Rondon’s lab). Photo Source: Oregon State University-Irrigated Agricultural Entomology Program (Silvia Rondon’s lab).
Photo source: Oregon State University – Oregon State Arthropod Collection.
A click beetle of the species Limonius californicus, the larvae of which are wireworms. A click beetle of the species Limonius canus, the larvae of which are wireworms.
A click beetle of the species Limonius californicus, the larvae of which are wireworms. A click beetle of the species Limonius canus, the larvae of which are wireworms.
Photo Source: Oregon State University – Oregon State Arthropod Collection.

 

On-Line Resources:

Pacific NorthwestInsect Management Handbook: Vegetable crop pests – Wireworm.

Managing Wireworms in Vegetable Crops. Ontario Ministry of Agriculture and Food

Wireworms. VegEdge, University of Minnesota.

Wireworms & Click Beetles. Washington State University.

Wireworm Field Guide - A guide to the identification and control of wireworms, Syngenta Crop Protection Canada, Inc.

Wireworm Biology and Nonchemical Management in Potatoes in the Pacific Northwest, N. Andrews, M. Ambrosino, G. Fisher, and S.I. Rondon, Pacific Northwest Extension Publication no. PNW607


Weeds

Common name: Field dodder
Latin binomial: Cuscuta spp.
Host Crops: Bean, beet, carrot, onion, pepper, potato, tomato, and many other crops (not only vegetables). Dodder is a parasitic plant that feeds on many other plant species. Dodder cannot photosynthesize, but produces haustoria that penetrate the host plant to absorb water and nutrients. Small, white to cream flowers are produced.
Photos: Carrot and Pepper

Photo of field dodder on pepper Photo of field dodder on carrot Photo of field dodder on carrot Photo of field dodder on carrot
The field dodder “net” can completely envelope, smother and kill crops. Dodder coiled on carrot leaves. Dodder on carrot. Dodder patch.
Photo Source: Michael Bush, WSU Extension, Yakima, WA Photo Source: Lindsey du Toit, Washington State University
Dodder (back) and nutsedge (front) in an onion bulb crop. Stems of a dodder plant in an onion bulb crop. Note the haustoria (protrusions) that the dodder forms to attach to and penetrate onion leaves. A severe infestation of dodder in an onion bulb crop. Note the clusters of small, white flowers.
Dodder (back) and nutsedge (front) in an onion bulb crop. Stems of a dodder plant in an onion bulb crop. Note the haustoria (protrusions) that the dodder forms to attach to and penetrate onion leaves. A severe infestation of dodder in an onion bulb crop. Note the clusters of small, white flowers.
Photo Source: Lindsey du Toit, Washington State University

On-Line Resources:

Pacific Northwest Plant Disease Management Handbook: Parasitic Plants of Oregon. Oregon State University Extension.

Pacific Northwest Weed Management Handbook. Chapter: Control of Problem Weeds, Section: Full chapter. pp 483–484, Oregon State University Extension.

http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7496.html

http://www.colostate.edu/Dept/CoopExt/4DMG/Weed/dodder.htm

http://pnwhandbooks.org/plantdisease/pathogen-articles/pathogens-common-many-plants/parasitic-plants-oregon


Common name: Yellow nutsedge
Latin binomial: Cyperus esculentus (Cyperaceae)
Plants affected: Any annual crop; the most seriously affected crops include onion and other plants with a light canopy and narrow range of herbicides available for use.

Photo of closeup view of a yellow nutsedge plant/flower Photo of severe nutsedge infestation in an onion crop
Closeup view of a yellow nutsedge plant/flower. Severe nutsedge infestation in an onion crop.

On-Line Resources:

Yellow Nutsedge. Identification & Management of Emerging Vegetable Problems in the Pacific Northwest, Pacific Northwest Vegetable Extension Group.
 

Abiotic Problems Common to Vegetables

Common name: Air pollution or ozone injury
Cause: During very hot conditions in summer, combined with the presence of excessive air particulate matter, e.g., from wildfires, symptoms of air pollution and/or ozone injury have been observed in center-pivot irrigated crops of various vegetables east of the Cascade Mountains in the Pacific Northwest USA.
Host Crops: Various vegetables such as bean, potato, and sweet corn.

Title Possible symptoms of ozone or air pollution injury to a sweet corn crop.
Symptoms of air pollution and possible ozone injury in a bean crop. Possible symptoms of ozone or air pollution injury to a sweet corn crop.
Photo Source: Lindsey du Toit, Washington State University Photo Source: Carrie H. Wohleb, Washington State University Extension


Problem: Blossom end rot of vegetable fruit
Cause: Calcium deficiency resulting from various environmental conditions and management practices, e.g., inadequate Ca in the soil, inconsistent water as a result of alternating wet and dry periods that decrease Ca uptake by plants, and even excellent growing conditions such as a period of very bright sunshine and warm temperatures mid-season.
Crops affected: Tomato, pepper, eggplant, and various cucurbits.

Photo of blossom end rot stymptoms on tomato Photo of blossom end rot stymptoms on tomato Photo of symptoms of blossom end rot on tomato fruit Photo of symptoms of blossom end rot on pepper
Symptoms of blossom end rot on tomato fruit. Symptoms of blossom end rot on tomato fruit. Blossom-end rot is a physiological disorder that first appears as a water-soaked, light brown spot on the distil end of the fruit. As the fruit matures, the spot becomes sunken, leathery, and brown to black. Secondary pathogens can infect the area, causing fruit rot. The disorder is more common on earliest maturing fruit. Blossom end rot is associated with a low concentration of calcium in developing fruit. In eastern Washington, this is often caused by excessive soil moisture fluctuations, drought stress, or excessive nitrogen fertilization. Soil surface mulches, appropriate irrigation timing and frequency, soil amendment with limestone, and foliar applications of calcium may reduce the incidence of this disorder.
Photo Source: Krishna Mohan, University of Idaho Photo Source: Carol Miles, Washington State University Photo Source: Mike Bush, WSU Yakima Co. Extension Educator

On-Line Resources:

Blossom-end-rot on Tomatoes. By M. Ophardt, 2013. WSU Extension Garden Tips.

Blossom end rot: Understanding a perennial problem. Michigan State University Extension.

Blossom-End Rot of Tomato, Pepper, and Eggplant. By Miller, S.A., R. C. Rowe, and R. M. Riedel, The Ohio State University Extension Fact Sheet HYG-3117-96.

Blossom-end Rot of Tomatoes. Oregon State University Extension Service Bulletin FS 139. By I.C. MacSwan, 2000. Oregon State University Extension Service Bulletin.

Vegetables: Tomato: Blossom-end Rot. Washington State University Hortsense.


 

Problem: General nutrient deficiencies and toxicities

On-Line Resources:

Plant Nutrient Functions and Deficiency and Toxicity Symptoms. By Ann McCauley, Montana State University Extension. This article provides information on nutrient management issues.


Problem: Stem splitting in brassica crops
Crops affected: Any brassica crop grown for seed can develop stem splitting under conditions that promote very rapid spring growth (high soil moisture and warm temperatures)
 

Photo of canola stem splitting Photo of canola stem splitting Photo of canola stem splitting Photo of canola stem splitting
Stem splitting in a winter canola crop in central Washington in spring (early May) resulting from very rapid growth under conditions of high soil moisture and sudden warm spring temperatures, following a supplementary nitrogen fertilizer application.
Photo Source: Karen Sowers, Washington State University Dept. of Crop & Soil Sciences

On-Line Resources:


Problem: Edema
A physiological problem that is prominent when air is cooler than the soil, soil moisture is high, and relative humidity is high. The low plant transpiration rate combined with an increase in water absorption by roots from the soil leads to increased cell turgor pressure, resulting in eruption of epidermal cells as the inner cells enlarge. Protrusion of the inner cells causes epidermal cells to die and discolor, resulting in a ’warty’ appearance that can be misidentified as a disease. Symptoms are usually worse on lower leaf vs. upper leaf surfaces.
Host Crops: Numerous vegetables including brassicas, cucurbits, peas, spinach, tomato, etc. Vegetables with waxy leaves, e.g., brassicas, tend to be most susceptible.
 

Photo of canola stem splitting Photo of canola stem splitting Photo of canola stem splitting Photo of canola stem splitting
Symptoms of edema on the lower surface of spinach leaves, showing burst and calloused epidermal cells. Symptoms of edema on the lower (abaxial) surface of a cabbage leaf, including calloused/warty protruberances from bursting of epidermal cells.
Photo Source: Pop Vriend Seed Co. Photo Source: Lindsey du Toit, Washington State University
Severe wart-like growths on a pumpkin caused by edema Close-up view of severe edema symptoms on a pumpkin Small but extensive symptoms of edema on a winter squash Close-up view of edema symptoms on the surface of a winter squash
Severe wart-like growths on a pumpkin caused by edema. Close-up view of severe edema symptoms on a pumpkin. Small but extensive symptoms of edema on a winter squash.Close-up view of edema symptoms on the surface of a winter squash.
Photo Source: Lindsey du Toit, Washington State University. Photo Source:
Phil Hamm, Oregon State University.
Photo Source: Lindsey du Toit, Washington State University.

On-Line Resources:

Cabbage and Cauliflower Brassica SP Oedema-Edema

Cabbage and Cauliflower Brassica SP Oedema-Edema

Edema Spring Crops

What are these bumps on my vegetables? Edema or oedema: It doesn’t matter how you spell it, it still doesn’t look good. What is it, what causes it and how can I prevent it? Michigan State University Extension


Problem: Vivipary (germination of seeds while still attached to the mother plant)
Crops affected: Solanaceaous vegetables like tomato and pepper.

Photo of symptoms of vivipary of tomato
This atypical tomato developed a dark discoloration just under the skin of the ripe fruit. When cut open, seeds within the tomato fruit were germinating. This physiological disorder is known as vivipary, where the seeds germinate while still in the fruit. It is suspected to be caused by plant stress such as drought, water stress, or potassium deficiency within the fruit. The fruit are still edible.
Photo Source: Michael Bush, Washington State University Extension, Yakima, WA

On-Line Resources:

Effect of potassium nutrition during bell pepper seed development on vivipary and endogenous levels of abscisic acid (ABA).. By Marrush, M., M. Yamaguchi and M. E. Saltveit. 1998. J. Amer. Soc. Hort. Sci. 123(5):925–930.

Physiological and Nutrient Disorders. University of Kentucky Vegetable Integrated Pest Management Program. Vegetable Manuals.

 

Herbicide Injury

Problem: Herbicide injury to vegetables

Cause: Various kinds of herbicides can cause injury to different types of vegetable crops depending on the mode of action, use pattern, timing of application, rate of application, crop rotation, etc. Always follow label instructions to avoid herbicide injury to crops.

Crops affected: All vegetables are prone to some kind of herbicide injury if the herbicide products are not used according to label instructions or vegetable crops are not planted in accordance with label herbicide instructions.

On-Line Resources:

Herbicide Modes and Action and Symptoms on Plants, Richard Smith, Farm Advisor, University of California Cooperative Extension.

Herbicide-related injury to plant species, including vegetables (~1100 images), University of California Statewide IPM Program.

Herbicide Mode of Action and Injury Symptoms, University of Minnesota Extension Service
 

Problem: Aminopyralid toxicity to vegetables from pre-plant compost application
Crops affected: bean, pea, pepper, tomato, spinach, etc. (almost any dicotyledonous plants)

Photo ofaminopyralid toxicity of pepper
Aminopyralid toxicity to pepper.

On-Line Resources:

Aminopyralid Residues in Compost and other Organic Amendments. Washington State University Whatcom County Extension.

Use of Compost on Organic Farms. Washington State Department of Agriculture, 8/30/2010.

The Allowance of Green Waste in Organic Production Systems. National Organic Program.

Problem: 2,4-D herbicide injury
Crops affected: Most vegetables are susceptible to 2,4-D injury

Photo of 2,4-D injury on cucurbit Photo of 2,4-D injury on tomato
2,4-D injury on cucurbit. 2,4-D injury on tomato.
Photo Source: Jenny Glass, WSU Puyallup PIDL

On-Line Resources:

Injury from 2,4-D. University of Illinois Extension Extension.

Herbicide Mode-Of-Action Summary. Cooperative Extension Service, Purdue University. See section I.A.1. Auxin Growth Regulators.

Herbicide Damage: 2,4-D and triclopyr. Hortsense, Washington State University. Click on Herbicide Damage, 2,4-D and triclopyr.

Vegetable Herbicide Damage. Colorado State University.

2,4-D Amine 4L injury symptoms on vegetables. University of Kentucky.
 


 

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Contact Us: Lindsey du Toit and Carol Miles