Variation in Brassica oleracea Resistance to Diamondback Moth (Lepidoptera: Plutellidae)1

Seventy-one lines and cultivars of different crucifer crops were evaluated for resistance to the diamondback moth, Plutella xylostella (L.). Larvae completed development on all lines and cultivars, but survival rate and feeding injury differed in some tests. In greenhouse experiments, moths preferred to oviposit on lines with dark-green leaves such as PI 234599 cauliflower and G 8329 cabbage, Chinese cabbages, and Pak choi. All crops with high egg deposition were also heavily damaged. However, in field tests, G 8329 cabbage, PI 234599 cauliflower, mature Chinese cabbages, and Pak choi were only lightly damaged by small numbers of larvae. Subsequent laboratory tests indicated that heavy mortality of early 1st-instar larvae occurred on G 8329 cabbage previously grown in the field.