YIELD LOSSES OF WHITE CABBAGE CAUSED BY COMPETITION WITH CLOVERS GROWN AS COVER CROP

To explore and develop intercropping as an integrated pest management tool to reduce population densities of pests in field grown vegetables , growth and yields of cabbage crops and clover cover crops were studi ed in four field experiments. In the first two experiments the clover crop had a clear pest reducing effect on fresh market cabbage. The ass ociated yield losses by competition with the cover crop ranged between 15-24%. In the other experiments, designed to explore possibilities t o reduce these yield losses in cabbage for storage, they ranged betwee n 18 and 43%. The decrease in weight per head could be reduced by decr easing the row distance from 0.75 m to 0.50 m, but the yield losses we re still high. Delay of sowing time of the clover crop or transplantin g the cabbage into a rotary cultivated strip in the clover stand, inst ead of transplanting in the clover stand itself, did not reduce yield losses. Intercropping with clover as an IPM tool is presently not read y for inclusion in cropping systems of cabbage and more detailed resea rch on interactions between cabbage, cover crops and pests is required .