Extension > Garden > Diagnose a problem > What's wrong with my plant? > Vegetable > Summer Squash and Zucchini > Rotten fruit
Summer Squash and Zucchini > Fruit > Rotten fruit
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Anthracnose
Colletotrichum obriculare
- Circular sunken dark spots on fruit up to ½” across
- Salmon colored spores form in the center of fruit spots when wet
- Irregular brown leaf spots
- Commonly appears mid to late season
- Also common on melons and cucumber
- More information on Anthracnose
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Scab
Cladosporium cucumerinum
- Cucumber, summer squash, zucchini, and pumpkin have sunken fruit spots are covered with greenish black velvety fungal growth
- Winter squash have raised corky areas around fruit infections, internal rot varies depending on resistance of variety
- Irregular gray leaf spot with a yellow halo
- Center of leaf spot falls out, leaves look shot holed or ragged
- Watermelon is very resistant
- More information on Scab
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Choanephora Rot
Choanephora cucurbitarum
- Blossom end of squash is soft, rotted and covered in fluffy purplish black fungal growth
- Flowers are covered with first white then purplish black fungal growth
- Occurs after wet weather
- Most common in squash
- More information on Choanephora Rot
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Gummy Stem Blight and Black Rot
Didymella bryoniae
- Fruit rot initially looks water soaked and eventually turns completely black
- Tiny black dots can be seen in fruit infections
- Fruit infection often starts on the side of the fruit touching the soil
- Fruit often collapse due to other rotting organisms
- Leaf symptoms vary from browning at leaf edges and between veins to circular tan to brown spots
- Yellow halos may occur around leaf spots and older spots are often dry and cracked
- Tan lesion on stems, often with black spots and dark gummy exudate
- More information on Gummy Stem Blight and Black Rot
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Phytophthora Blight
Phytophthora capsici
- Fruit develop soft, water-soaked lesions which expand to large sections of the fruit
- Infected fruit are soft, easily punctured and often collapse
- Infected fruit are covered with white fungal growth
- Large irregular brown spots on leaves
- Stem and leaf petiole lesions are light to dark brown, water soaked and irregular
- The entire plant may collapse if root and crown rot occurs
- More information on Phytophthora Blight
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White Mold
Sclerotinia sclerotiorum
- Fruit becomes rotted and watery
- White cottony mold on squash
- Small hard, black raisin like fungal structures embedded in cottony mold
- Most common on pumpkin and some winter squash
- More information on White Mold
