|last year my grapes(thompson seedless) produced alot. then dried on the vine before they got ripe, why?
|Answer from NGA
March 7, 2010
|There are two physiological problems with nearly the same symptoms: berry shrivel and bunch stem necrosis. Both are being studied at the university level so causes and cures are still mostly unknown. With berry shrivel, the grapes look fine until they begin to ripen. When they begin converting their sugar, they shrivel up. The symptoms of bunch stem necrosis can affect whole clusters or sometimes just a few grapes within the clusters. The researchers are leaning toward a phosphorus deficiency in the soil as the cause. Since I can't suggest a cure I can only suggest that you keep your vines watered regularly and be sure to feed with a 5-10-5 to encourage flower and fruit formation. Best wishes with your grapevines.
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