Yield losses of white cabbage caused by competition with clovers grown as cover crop

The use of intercropping as an integrated pest management (IPM) tool to reduce population densities of pests of field grown vegetables, and the growth and yields of cabbage and clover cover crops grown in the Netherlands, were investigated. In the first 2 experiments, the clover (Trifolium repens cv. Pertina or T. subterraneum cv. Geraldton) crop significantly reduced pest damage of fresh market cabbage cv. Minicole. The associated yield losses due to competition with the cover crop were 15-24%. In other experiments designed to investigate these yield losses in cabbage for storage (cv. Slawdena), the losses were 18-43%. The decrease in weight/head was reduced by decreasing the row distance from 0.75 to 0.50 m, although yield losses were still high. Delaying the sowing of the clover crop, or transplanting the cabbage into a rotary cultivated strip in the clover stand instead of transplanting in the clover stand itself, did not reduce yield losses. It is suggested that intercropping with clover as an IPM tool is not suitable at present for cabbage crops in the Netherlands.