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Cucurbits

Identify Fruit Damage—Harvest

During harvest, record the type of fruit damage you see to assess this year’s pest management results and to plan for next year.

Names link to information on identification and management.

Pumpkins
Lesions on pumpkin caused by the Fusarium crown and foot rot pathogen.
Fusarium crown and foot rot lesions
Identification tip: Fruit lesions are firm and dry, with the decayed area exhibiting a concentric ring pattern.
A pumpkin fruit infected with Phytophthora capsici showing a lesion with downy growth.
Phytophthora species infection
Identification tip: First appears as a water-soaked lesion. Lesion spreads and becomes covered with white mold.
 
Yellow squash
Watermelon mosaic virus symptoms on yellow squash.
Potyvirus symptoms
Identification tip: Fruit has mottled surface.

Mosaic pattern and deformed zucchini fruit caused by Squash mosaic virus.
Squash mosaic virus symptoms
Identification tip: Fruit can be deformed and mottled.
 
Cantaloupe
Canopies with vine decline caused by Monosporascus cannonballus eventually collapse leaving fruit exposed to sun scalding..
Vine disease decline (Monosporascus cannonballus)
Identification tip: Fruit of infected plants may be dislodged from the vine and show symptoms including reduced size, lower sugar content and sunburn (due to lack of foliage).
   
Zucchini
Zucchini fruit with symptoms of Cucumber mosaic virus (center) has a warty surface.
Cucumber mosaic symptoms
Identification tip: Symptoms include misshapen fruit, a bumpy surface, and discoloration.
Zucchini fruit infected with Watermelon mosaic virus (top) can develop knobby overgrowths.
Potyvirus symptoms
Identification tip: Fruit can be misshapen and have a knobby surface.
 
Cucumbers
Fruit damaged by weather (heat).
Heat damage
Identification tip: Plants that were exposed to extreme heat early in development produce underdeveloped fruit.

Discoloration of cucumber flesh found below surface lesions is a symptom of angular leaf spot caused by Pseudomonas syringae.
Angular leafspot symptoms
Identification tip: Water soaked spots turn tan. Below the lesions, flesh may be brown down to the seed layer.

Soft, water-soaked, yellow ends of cucumber with gray mold caused by Botrytis cinerea.
Botrytis damage
Identification tip: Soft, water-soaked, yellow ends of cucumber with gray mold caused by Botrytis cinerea.
Honeydew
Measles, an abiotic disorder caused by wet soils, causes melon fruit to have water-soaked spots with centers that will eventually become tan.
Measles symptoms
Identification tip: Small lesions cover fruit surface.
Sunburn on honeydew melon characterized by a discolored tender area on the rind.
Sunburn damage
Identification tip: An area of the surface is discolored and tender.

The surface of honeydew melon infected with Watermelon mosaic virus can develop knobby overgrowths.
Potyvirus symptoms
Identification tip: Affected fruit have small sunken depressions.
Feeding scars on a honeydew melon rind caused by western striped cucumber beetle, Acalymma trivittatum.
Cucumber beetle damage
Identification tip: Cucumber beetle feeding on fruit causes scarring.
   
Watermelon
Watermelon fruit infected with Watermelon mosaic virus (top) can develop knobby overgrowths.
Potyvirus symptoms
Identification tip: The affected fruit can be misshapen and have a severely knobby surface.
A watermelon fruit infected with Phytophthora capsici showing a brown, soft sunken lesion with a dark center.
Phytophthora species symptoms
Identification tip: Irregular brown spots grow rapidly into round to oval lesions with rotted centers and eventually grayish fungal growth covers the centers of rotted areas.
 
Casaba
Lesions on casaba caused by the Fusarium crown and foot rot pathogen, Fusarium solani f. sp. cucurbitae.
Fusarium crown and foot rot lesion
Identification tip: Fruit lesions are firm and dry, with the decayed area exhibiting a concentric ring pattern.
   

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