Pacific Northwest Vegetable Extension Group

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

Photo Gallery of Vegetable Problems

Pumpkin

(Click on photo to enlarge)

Diseases

Disease: Curly top
Pathogen: Various strains of Beet curly top virus (BCTV), which are vectored by the beet leafhopper (Circulifer tenellus)
Host crops: Numerous plant species including many vegetables such as bean, beet, carrot, eggplant, coriander, pepper, potato, tomato, various cucurbits such as squash, cucumber, pumpkin, watermelon, etc.

Photo showing symptoms of curly top on pumpkin leaves Photo of symptoms of curly top on pumpkin crop Photo of symptoms of curly top on pumpkin crop Phot of curly top symptoms on acorn squash leaves
Symptoms of curly top on pumpkin leaves. Note yellowing of the foliage. Symptoms of curly top in an acorn squash crop.
Photo Source: Ken Eastwell, Washington State University virologist Photo Source: George Clough, Oregon State University Photo Source: Phil Ham, OSU plant pathologist
Photo of symptoms of curly top on squash leaves
Symptoms of curly top in a squash crop.
Photo Source: Phil Ham, OSU plant pathologist

On-Line Resources:

Pacific Northwest Plant Disease Management Handbook: Squash (Cucurbita spp.) – Curly Top
 

Disease: Powdery mildew
Pathogen: Golovinomyces cichoracearum (formerly Erysiphe cichoracearum) and Podosphaera fuliginea (formerly Sphaerotheca fuliginea)
Host crops: All cucurbit vegetables (e.g. cucumber, cantaloupe, melon, pumpkin, and squash). There are different races of the pathogens.

Photo of Powdery mildew on pumpkin
Photo Source: G.Q. Pelter

On-Line Resources:

Cucumber, Pumpkin, Squash: Powdery Mildew, Washington State University Hortsense

Disease: Root Rot
Pathogen: Pythium

Photo of phthium root rot of pumpkin Photo of phthium root rot on pumpkin
Pumpkin seedling. Microscopic view of roots with round, thick-walled oospores of Pythium embedded in the root tissues.
Photo Source: Jenny Glass

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

Pacific Northwest Plant Disease Management Handbook: Cucumber (Cucumis sativus) – Damping-off
 

Disease: Suspected zucchini yellows + watermelon mosaic virus
Pathogen:  

Photo of suspected zucchini yellows plus watermelon mosaic virus on pumpkin
Photo Source: G.Q. Pelter

On-Line Resources:

Disease: Suspected virus
Pathogen: Unknown

Photo of suspected virus on pumpkin
Photo Source: G.Q. Pelter

On-Line Resources:

Disease: Verticillium wilt
Pathogen: Verticillium species
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 on pumpkin 'We-Be-Little' Photo of Verticillium wilt on pumpkin 'We-Be-Little'
Pumpkin ‘We-Be-Little’
Photo Source: D.A. Inglis

On-Line Resources:

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

See Diseases, pests, and other problems common to many vegetables: Verticillium wilt.
 

Insect/Mite Pests

Common name: Bean aphid, green peach aphid, melon aphid, and potato aphid
Latin binomial: Aphis fabae , Myzus persicae, Aphis gossypii, and Macrosiphum euphorbiae respectively
Host crops: In addition to tomato, eggplant and pepper, bean, melon, sweet corn, corn seed, carrot, cucumber, and eggplant the bean aphid can feed on spinach, Swiss chard, squash, pumpkin, and beet. The green peach aphid can feed on potato, tomato, eggplant, pepper, broccoli, cabbage, spinach, Swiss chard, squash, pumpkin, beet and many weed species including Brassicaceae (cruciferous) weeds. The melon aphid can feed on cucumber, melon, pumpkin, squash, spinach and spinach seed. The potato aphid can feed on cucumber, potato, melon, tomato, pumpkins, squash, and corn seed.

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:

Pacific Northwest Insect Management Handbook: Vegetable crop pests-Aphid

Pacific Northwest Insect Management Handbook: Pumpkin and squash – Aphid

Common Insect & Mite: Aphids, Washington State University Hortsense

See Diseases, pests, and other problems common to many vegetables: Aphids

For aphids on other crops see: potato, and squash
 

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. Hosts and Pests of Vegetable Crops. Scroll down for Pumpkin and Squash section.

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

See See Diseases, pests, and other problems common to many vegetables: Squash bug.
 

Common name: Western flower thrips
Latin binomial: Frankliniella occidentalis.
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 thips
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. Immature Western flower thrips resemble the adults but are smaller, wingless and translucent yellow in color. There are 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.
Photo Source: Michael Bush, WSU Extension, Yakima, WA

On-Line Resources:

Western Flower Thrips Thysanoptera: Thripidae Frankiniella occidentalis,

Cucurbits: Thrips, UC IPM Online, University of California

See Diseases, pests, and other problems common to many vegetables: Western flower thrips.

Abiotic Problems

Problem: Edema
A physiological problem: prominent when air is cooler than the soil, soil moisture is high, and relative humidity is high. The low plant transpiration rates 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. In addition to foliar symptoms on some hosts, many cucurbit crops develop wart-like protruberances on the fruit.
 

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:

http://www.omafra.gov.on.ca/english/crops/facts/00-031.htm#oedema

http://www.ces.ncsu.edu/depts/pp/notes/oldnotes/gp3.htm

Our pages provide links to external sites for the convenience of users. WSU Extension does not manage these external sites, nor does Extension review, control, or take responsibility for the content of these sites. These external sites do not implicitly or explicitly represent official positions and policies of WSU Extension.

WSU Mount Vernon NWREC, 16650 State Route 536, Mount Vernon, WA 98273-4768, 360-848-6120
Contact Us: Lindsey du Toit and Carol Miles