Diseases of Cucurbits

Gummy stem blightGummy stem blight of watermelon

Gummy stem blight of watermelon

Gummy stem blight of muskmelon

Gummy stem blight of muskmelon

Fungal structures-sign.

Didymella bryoniae, causal agent of gummy stem, blight on stem.

Didymella bryoniae conidia released in columns from pycnidia.

Gummy stem blight management•Crop rotation ~3 years•Fall tillage•Field/greenhouse sanitation•Timely fungicide applications

anthracnose of watermelon

anthracnose of muskmelon

anthracnose of cucumber

Anthracnose management•Crop rotation ~3 years•Fall tillage•Field/greenhouse sanitation•Timely fungicide applications

anthracnose of watermelon

Bacterial Fruit Blotch

Bacterial fruit blotch management•Crop rotation ~2 years•Fall tillage•Field/greenhouse sanitation•Timely fixed copper applications

Bacterial fruit blotch of watermelon

Fusarium wilt of watermelon

Vascular discoloration

Fusarium wilt of watermelon/fungal

Alternaria leaf blight of muskmelon

Alternaria leaf blight of muskmelon

Alternaria leaf blight of muskmelon

Alternaria leaf blight management•Crop rotation ~2 years•Fall tillage•Timely fungicide applications

Powdery mildew of cucumber

Movement in plantActive ingredient On

surface (contact)

Limitedmovement(systemic)

Primary uses

chlorothalonil X Many fungal diseasesmancozeb X Many fungal diseasescopperhydroxide/sulfate

X Limited use on fungaldiseases

captan X Many fungal diseasessulfur X Powdery mildew, mitesazoxystrobin X Leaf spot diseasesmyclobutanil X Powdery mildewpyraclostrobin X Leaf spot, rust diseasestebuconazole X Leaf spot diseasespropaconazole X Leaf spot, rust diseases

Comparison of several fungicide active ingredients

Follow the label including:• Wear protective clothes

like gloves• Use the correct rate• Make sure crop is on the

label• Wash hands before

eating.

Bacterial wilt of muskmelon

Streaming or oozing with cut stemscaused by bacterial wilt.

Bacterial wilt of muskmelon

Bacterial streaming

Diseases of pumpkin

Powdery mildew of pumpkin

Healthy variegated pumpkin leaves

Powdery mildew management•Crop rotation ~2 years•Fall tillage•Partial resistance•Timely systemic fungicide applications

Virus diseases of pumpkin

Virus diseases of pumpkin

Virus diseases of pumpkin

Virus disease management•Aphid transmitted•Insecticides ineffective against virus spread•Planting date

Downy mildew-pumpkin

Downy mildew-pumpkin

Downy mildew-pumpkin

Downy mildew-pumpkin

Downy mildew management•Scout fields•Follow epidemic•Timely use of specialized systemic fungicides

Phytophthora blight of pumpkin

Phytophthora blight of watermelon

Cucumber culls withPhytophthora blight

Phytophthora blight may arrive oncrop culls

Phytophthora blight

Phytophthora blight management•Crop rotation >4 years•Water management•Field sanitation•Specialized fungicides

Bacterial spot pumpkin

Bacterial spot pumpkin

Bacterial spot pumpkin

Bacterial fruit spot management•Crop rotation ~3 years•Fall tillage•Monitor seed source•Weed management•Field/greenhouse sanitation•Timely fixed copper applications

Root knot nematode•Many hosts, melons, pumpkins, tomato

Root knot nematode•Avoid field with high populations of RKN•Brassica cover crops may help•Fumigants may be used

Fungicide applications for melons

•Is it for you?•Know the disease/product•Safety•Measure carefully•Anticipate the disease•Be ready to repeat

Start fungicide applications before disease appears

Lesions of Septoria leaf spot on tomato

Disease lesions start to small to see.

Insects are visible or not.

Scout for insects pests—then apply insecticides

Cornell

Muskmelon/Watermelon fungicide schedule

May June July August

Mancozeb fungicide (contact) for gummy stem blight & anthracnose

Tebuconazole fungicide for powdery mildew, gummy stem blight & anthracnose