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Photo Gallery of Vegetable Problems – Squash

Diseases

Angular leaf spot

Curly top

Powdery mildew

Mosaic

White mold

Insect/Mite Pests

Aphids Squash bug Western flower thrips

Abiotic Problems

Edema

(Click on photo to enlarge)

Diseases

Disease: Angular leaf spot
Pathogen: Pseudomonas lachrymans

Photo Source: D.A. Inglis

Online Resources:

Pacific Northwest Plant Disease Management Handbook: Squash (Cucurbita spp.) – Angular Leaf Spot

Cucumber, Pumpkin, Squash: Angular leaf spot, Washinton State University Hortsense

Disease: Curly top
Pathogen: Curly top virus
Host crops: Numerous plant species including many vegetables such as bean, beet, carrot,eggplantcoriander, pepper, potatotomato, and various cucurbits such as squash,cucumberpumpkinwatermelon, etc.

Photo Source: E. J. Sorensen Photo Source: Phil Ham, OSU plant pathologist

Online Resources:

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

Cucumber, Pumpkin, Squash: Curly top (Beet curly top virus), Washington State University Hortsense

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, andsquash). There are different races of the pathogens.

Photo Source: D.A. Inglis Photo Source: Lyndon Porter, USDA-ARS

Online Resources:

How to Manage Pests: Pests in Gardens and Landscapes: Powdery Mildew on Vegetables. UC IPM Online, University of California

Pacific Northwest Plant Disease Management Handbook: Squash (Cucurbita spp.) – Powdery Mildew

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

Disease: Mosaic
Pathogen: Suspected watermelon mosaic virus

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Photo Source: E. J. Sorensen

Online Resources:

Pacific Northwest Plant Disease Management Handbook: Squash (Cucurbita spp.) – Virus Diseases

Common name: White mold
Latin binomial: Sclerotinia sclerotiorum
Host cropsCucurbit vegetables (e.g. cucumber, pumpkin, and squash), pepper, snap bean, carrot, cabbage, cauliflower, lentil, field pea, potato, radish, and many weed species.

White mold infecting of a gourd of a squash plant. Pathogen bleaches the vines white. Black sclerotia (dormant survival structures) of the pathogen are often produced inside infected vines.
Photo Source: Lyndon Porter, USDA-ARS

Online Resources:

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

Fruit Rots of Squash and Pumpkins: Sclerotinia White Mold, Vegetable MD Online, Cornell University

White Mold of Vegetables, Pest Management Fact Sheet #5084, The University of Maine

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 euphorbiaerespectively
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 Source: Michael Bush, WSU Extension, Yakima, WA

Online 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: Green peach aphid

For aphids on other crops see: potato, and pumpkin

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

Photo Source: Michael Bush, WSU Extension, Yakima, WA

Online Resources:

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

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 cropsBasilBroccoliCabbageCauliflowerCucumberOnionPotatoPumpkin, Squash,Tomato and Watermelon.

Photo Source: Michael Bush, WSU Extension, Yakima, WA

Online 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

ProblemEdema
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.

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