SELECTION FOR RESISTANCE TO DIAMONDBACK MOTH (PLUTELLA-XYLOSTELLA) IN CABBAGE

Inbreds and hybrid cabbage (Brassica oleracea var. capitata) selected for resistance to diamondback moth (DBM, Plutella xylostella L.) were tested in the field in New York and Honduras for resistance. In New York, plants were inoculated with up to 400 eggs per plant to enhance the severity of the tests. In Honduras, where natural populations of DBM were high, especially in the dry season, there were three distinct classes of susceptibility to DBM: the very susceptible controls or standard cultivars, the highly resistant glossy-leaved lines, and the intermediate selections with normal leaf bloom. Some normal-leaf hybrids were more resistant than either of their parents, which indicates the need to select for specific combining ability for high resistance levels. At maturity, the glossy-leaved hybrids produced marketable crops without aid of chemical sprays.