Studies on the cultural control of virus diseases in zucchini crops

Aphid-borne viruses ( CUCUMBER MOSAIC virus, Watermelon mosaic virusl/Ig 2, Watermelon mosaic virusl/Ig - Morocco strain, and Zucchini yellow mosaic virus ) are a threat to the production of zucchini crops in KwaZulu-Natal. Seven different non-chemical control options were compared for their effectiveness in reducing aphid vector numbers and viral disease in a zucchini field in the KwaZulu- Natal Midlands. The best treatments in reducing disease incidence were a yellow-brown plastic mulch (cost R4920/ha) (yellow side facing up), floating row-covers (R5040/ha) and a shadenet mulch (R87 780/ha). These treatments also produced the most fruit (lIgPl/Ig = 0.027) and improved the fruit mean weight (lIgPl/Ig = 0.009), and in addition successfully reduced aphid numbers (lIgPl/Ig = 0.02). The shadenet mulch is too expensive to be used as a control measure. We recommend that a plastic mulch be used in conjunction with row-covers to prevent weed growth. Drip irrigation is recommended for use with all these treatments.