Causal Agent:
Fungus (Choanephora cucurbitarum)
Characteristic Symptoms: | ||
Affected flowers, pedicels (flower stalks), and immature fruit become water-soaked, and a soft wet rot develops. The fruit resembles a pincushion with numerous small, black-headed pins stuck in it. Flowers are covered with white then purplish black fungal growth. | ||
An entire fruit can rot in a 24- to 48-hour period. | ||
Conditions for Disease Development: | ||
Development of wet rot is favored by high relative humidity and excessive rainfall. | ||
The fungus survives from season to season in crop debris and is spread to new flowers by insects, splashing water, or wind.
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Infection most commonly occurs on flowers, although the fungi can also infect through wounds on the fruit. Infected flowers are soft, rotted and quickly become covered | ||
With first white then purplish black fungal growth. In female flowers, the infection progresses into the fruit and results in soft water rot of the blossom end. |
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Management and Control: | ||
Control of wet rot is difficult.
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In small plantings or gardens, hand removal of flower parts, particularly squash, after fruit set will reduce this problem. | ||
Avoid picking southern peas when they are green and storing them under wet conditions.
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Fungicides are ineffective against Choanephora wet rot because new blossoms or flowers open every day. | ||
Practice crop rotation. | ||
Avoid overhead irrigation. | ||
Space plants to provide adequate air movement in the field to quickly dry flowers and fruit. | ||
Raised plant beds and plastic mulch may be of help to limit fruit contact with moist soil and reduce moisture in the lower plant canopy. |
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