Fruit or Soil Rots

        

       Soil fruit fungal rot is caused mainly by Pythium aphanidermatum and Rhizoctonia solani but also by Botrytis cinerea, other Pythium species, and Rhizopus stolonifer, is a serious disease of cucumbers in Hawaii. The disease results in up to 60% yield losses. The disease infects fruit in contact with the soil resulting in rotting and in fruit scars. Cottony leak, caused by a Pythium spp., is the most common cucumber fruit rot in Hawaii. Fruit symptoms include a soft and watery white fungus covering the skin. Attacks of this fungus on young seedling also causes typical damping-off. Soil rot in cucumbers caused by Rhizoctonia is less common in Hawaii. Fruit lesions from Rhizoctonia begin as dark-green water soaked areas, then affected tissues collapse leaving small holes in the fruit which eventually dry-up. A brownish mycelial growth on the lesions appears in affected fruits during continuous humid conditions. Fruit rots are partially controlled with trellises and plastic mulches. Recommended cultural practices for Pythium control include disking the soil 3-4 weeks prior to planting to completely decompose old organic matter which helps to prevent the disease organism from surviving in the soil. Fungicidal sprays may be effective in controlling this disease. No cultivar resistance exists to fruit rots in the cucurbits.