Film-Coating Seeds with Chlorpyrifos for Germination and Control of Cabbage Maggot (Diptera: Anthomyiidae) on Cabbage Transplants

The cabbage maggot, Delia radicum (L.), is an important chronic pest of cabbage in the northern U.S. The maggots of this species cause damage to young plants by feeding on roots and stems, resulting in plant stand and yield losses or rendering the crop unmarketable. In New York, the nation's largest producer of cabbage, the most common control practice is to apply a drench or banded spray of chlorpyrifos at transplanting. As an alternative to this practice, we investigated the duration of insecticidal activity of chlorpyrifos film-coated seeds on cabbage transplants. Seeds of the cabbage var. ‘Fresco F-1’ were film-coated with chlorpyrifos at the rates of 0, 9.6, 19.2 or 28.8 g [Al]/kg seed and then examined for phytotoxic effects on germination in the laboratory as well as effectiveness against immature stages of D. radicum under greenhouse and field conditions. Chlorpyrifos film-coated seed treatments did not adversely affect germination in the laboratory tests when plants were grown with peat soil in transplant cell trays and provided significant plant protection against immature stages of cabbage maggot through several weeks after transplanting seedlings with associated soil under greenhouse and field conditions. These results agree with previous European studies showing the potential of seed treatments to reduce damage by D. radicum while at the same time dramatically reducing the amount of insecticide compared with a banded spray or drench application.