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Alternaria leaf blight Anthracnose Glyphosate injury Gummy stem blight Phytophthora Pumpkin fruit rot Pumpkin Downy mildew Virus complex

Plant: Watermelon (Citrullus lanatus) (Cucurbitaceae) Back to List
Disease/Disorder: Gummy stem blight
Causal agent: Didymella bryoniae (fungus) Phoma cucurbitacearum (anamorph, pictured)
Signs: spore-producing bodies ("pycnidia") can be seen within leaf spots.
Symptoms: darkened leaf spots usually with concentric rings
Total image number: 12
The disease has a stem blight phase which is not pictured.

Plant: Cucumber and Muskmelon (Cucumis sativus and Cucumis melo subsp. melo) (Cucurbitaceae)
Back to List
Disease/Disorder: Anthracnose
Causal agent: Colletotrichum orbiculare (fungus)
Signs: spore-producing bodies ("acervuli") with dark sterile hairs ("setae") can be seen within blighted areas
Symptoms: spotting on leaves and tan lesions on the leaf petioles and stems
Total image number: 12
1st and last row is of cucumber
Middle row is of muskmelon

Plant: Cucumber and Muskmelon (Cucumis sativus and Cucumis melo subsp. melo) (Cucurbitaceae)
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Disease/Disorder: Phytophthora fruit rot, Phytophthora root and crown rot
Causal agent: Phytophthora capsici (fungus)
Signs: white mycelium with spore-producing bodies ("sporangia")
Symptoms: white mold on blighted portions of fruit and stems
Total image number: 16
1st 3 rows are of cucumber - these images show the fruit rot phase
4th row is squash - these images show the crown/stem rot phase

Plant: Muskmelon and Cantaloupe (Cucumis melo subsp. melo) Back to List
Disease/Disorder: Alternaria leaf blight
Causal agent: Alternaria cucurmerina (fungus)
Signs: dark spores of this fungus are rather large and can be seen with a hand lens.
Symptoms: tan to brown spotting on leaves
Total image number: 11
1st and 2nd row is of muskmelon
3rd row is of cantaloupe

Plant: Squash (Cucurbita spp.) (Cucurbitaceae) Back to List
Disease/Disorder: Virus complex
Causal agent: (virus)
Signs:
Symptoms: distorted leaves with mosaic blotches
Total image number: 4
All we can say, without sending the sample off for a Cucurbit Virus Screen, is that it is one of the viruses and list the complex of cucurbit viruses: Cucumber mosaic (CMV), Watermelon mosaic (WMV), Zucchini yellow (ZYMV), Papaya ring spot virus type W (PRSV-W), and Squash mosaic (SqMV).

Plant: Pumpkin (Cucurbita spp.) (Cucurbitaceae) Back to List
Disease/Disorder: Fruit rot
Causal agent: Fusarium spp. (fungus)
Signs: white/tan mycelium and spores masses
Symptoms: white to tan spots on fruit with subsequent fruit decay
Total image number: 14
1st row is a standard pumpkin.
2nd, 3rd, and 4th rows are from 'Lil ironsides' cultivar, Fusarium solani.

Plant: Pumpkin (Cucurbita spp.) (Cucurbitaceae) Back to List
Disease/Disorder: Downy mildew
Causal agent: Pseudoperonospora cubensis (fungus)
Signs: downy mycelial growth in spots
Symptoms: yellow blotchy areas with mold
Total image number: 4

Plant: Cantaloupe (Cucumis melo subsp. melo) Back to List
Disease/Disorder: herbicide injury
Causal agent: "Roundup" 'glyphosate'
Signs:
Symptoms: Yellowing of youngest leaves from the base.
Total image number: 4