Photo Gallery of Vegetable Problems
Squash
(Click on photo to enlarge)
Diseases
Disease: Angular leaf spot
Pathogen: Pseudomonas lachrymans
Photo Source: D.A. Inglis |
On-Line 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, eggplant, coriander, pepper, potato, tomato, and various cucurbits such as squash, cucumber, pumpkin, watermelon, etc.
Squash, butternut | Squash, winter | Symptoms of curly top in an acorn squash crop. | Symptoms of curly top in a squash crop. |
Photo Source: E. J. Sorensen | Photo Source: Phil Ham, OSU plant pathologist |
On-Line 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, and squash). There are different races of the pathogens.
Photo Source: D.A. Inglis | Photo Source: Lyndon Porter, USDA-ARS |
Photo Source: Lyndon Porter, USDA-ARS |
On-Line 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
On-Line Resources:
Pacific Northwest Plant Disease Management Handbook: Squash (Cucurbita spp.) – Virus Diseases
Common name: White mold
Latin binomial: Sclerotinia sclerotiorum
Host crops: Cucurbit 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. | White mold on squash vines. | ||
Photo Source: Lyndon Porter, USDA-ARS |
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 |
On-Line 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 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.
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: 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).
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.
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.
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.
On-Line Resources:
https://www.omafra.gov.on.ca/english/crops/facts/00-031.htm#oedema
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