Insect Populations on Cabbage Grown with Living Mulches

Cabbage was grown interplanted with several living mulches and in bare-ground monocultures in 1982 and 1983 at Freeville, N.Y. Living mulches were creeping bentgrass, red fescue, Kentucky bluegrass, and two white clovers. Populations of Phyllotreta cruciferae Goeze and Brevicoryne brassicae (L.) were lower on cabbage grown with any living mulch than on cabbage in bare-ground monocultures. First-generation larvae of Pieris rapae (L.) were more common on cabbage with clover living mulches, but second-generation eggs and larvae were less common on cabbage with clover living mulches. These differences in population density were probably determined by variation in herbivore colonization rates, not by variation in herbivore mortality. The data suggest that early season chemical treatments for flea beetles might be eliminated when living mulches are used. However, this potential gain may be offset by yield reduction from competition between cabbage and living mulches.