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Photo Gallery of Vegetable Problems – Watermelon


Diseases

Curly top

Damping-off/Seedling blight

Verticillium wilt White mold

Insect/Mite Pests

Western flower thrips

Abiotic Problems

Edema

(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,eggplantcoriander, pepper, potatotomato, various cucurbits such as squashcucumber,pumpkin, watermelon, etc.

Photo Source: Ken Eastwell, Washington State University virologist Photo Source: Phil Ham, OSU plant pathologist

 

Online Resources::

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

Disease: Damping-off/Seedling blight
Pathogen: Pythium
Host crops: Most vegetables are susceptible to damping-off/seedling blight.

 watermelon-seedling-blight-1L
Photo Source:Lindsey du Toit

Online Resources::

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

See Diseases, pests, and other problems common to many vegetables: Damping-off/seedling blight.

Disease: Verticillium wilt
Pathogen: Verticillium species
Host crops: Numerous vegetables including many brassica vegetables (but not broccoli), cucumber, eggplant, pepper, potatopumpkin, radish, spinachtomato, watermelon, etc.

Photo Source: Sacha Johnson

Online Resources::

Pacific Northwest Plant Disease Management Handbook: Watermelon (Citrullus sp.) – Verticillium Wilt

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

Insect/Mite Pests

 

Common name: Western flower thrips
Latin binomial: Frankliniella occidentalis.
Host cropsBasilBroccoliCabbageCauliflowerCucumberOnionPotatoPumpkinSquash,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.

 

Online 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