Cucurbit Crops Pest Identification Indicates very common pests
Powdery mildew: white spots and growth, especially on underside of leaves, dries out stems
Downy Mildew: square-ish yellow or brown leaf spots/dark fuzz below/curling, wilting leaves
Cucurbit Pests Photo by R. Wick, UMass Black rot: black or brown spots with rings = gummy stem blight: gummy droplets leaking from vines
Cucurbit Pests Photo by R. Wick, UMass Photo by R. Wick, UMass Plectosporium blight: white, diamond-shaped lesions on vines/round on fruit & leaves/kills vines
Phytophthora blight: flour-like growth on fruit or vines, fruit rot, vines collapse and die
Photo by R. Wick, UMass Scab: White spots on leaves, sunken spots on fruit Cucurbit Pests
Photo by W. Elmer, CAES Fusarium crown and fruit rot: brown and white, sunken spots on fruit/brown stems
Sclerotinia fruit rot: white growth like shavingcream with large dark resting spores
Alternaria leaf spot: tan or black leaf spots on older foliage. Spots may develop concentric rings Cucurbit Pests
Anthracnose: brown or tan leaf spots on cucumbers/ sunken stem lesions with tan spores/round, sunken, dark fruit lesions, often with salmon-colored spores Cucurbit Pests Photos by R. Wick, UMass
Photo by R. Wick, UMass Bacterial wilt: plants wilt and die/leaves have water-soaked areas between veins/bacteria shown streaming out of cut stem
Angular leaf spot: irregular to angular shaped spots, tissue turns dark and tears
Photos by M. McGrath, Cornell University Bacterial leaf spot: fruit spots with soft, brown halo/leaf spots white with yellow halo
Cucurbit yellow vine: yellow leaves/brown tissue in stem, spread by squash bugs
Photo by R. Wick, UMass Virus: distorted leaves and fruit (shape and/or color)
Sun scald: large pale area facing sun, may turn black as fungus attacks dead tissue
Photo by J. Howell, UMass Aborted fruit: due to lack of pollination, small fruit turn brown at blossom end and eventually drop off plant
Drought damage: dead tissue on leaf margins
Ozone damage: interveinal clearing
clomazone herbicide injury: young foliage turns white, ethalfluralin turns them yellow
Striped cucumber beetle: yellow and black stripes/ defoliates seedlings/scars fruit/spreads bacterial wilt Photo by R. Durgy, CAES Cucurbit Pests
Photo by D. Ferro, UMass Spotted cucumber beetle: larger leaf holes
Flea beetles: small, dark beetles that jump like fleas/ make small pits or holes in leaves
Photo by R. Durgy, CAES Squash bugs: eggs brown/nymphs grey and soft/adults hard and brown/leaves and plants wilt, spreads cucurbit yellow vine
Squash vine borer: day-flying orange and black moth /large white larvae/bore into vines, vines may wilt
Squash beetles: large, orange ladybug/larvae yellow with black bristles/circular, lacey, leaf holes/spiral scars on fruit
Melon aphids: small, dark, pear-shaped, with dark tail pipes. Usually found on underside of leaves
Spring tails: small, dark, wingless, jump like fleas/make pits and small holes in seedling leaves
Ground hog damage: shallow scaring of fruit
Deer damage: deep holes in fruit, eat flesh and seeds