Pest management on Guam for Head Cabbage Production

Cruciferous crops on Guam are infested by cabbage webworm, Hellula undalis (F.), cabbage cluster caterpillar, Crocidolomia pavonana Zeller, mustard aphid, Lipaphis erysimi (Davis), armyworm, Spodoptera litura (F.), flea hopper, Halticus tibialis (Reuter), fire ant, Solenopsis geminata (F.), leaf miners, Liriomyza spp., diamondback moth, Plutella xylostella (L.), corn earworm, Helicoverpa armigera (Hübner), and garden looper, Chrysodeixis chalcites (Esper.). Because cabbage (Brassica oleracea var. capitata L.) is one of the economically important vegetables on Guam, we have been developing an integrated pest management program for this crop. Hellula undalis is a serious problem on seedlings in nurseries as well as transplanted young plants in the field. Naled was effective in contolling this pest on young seedlings. Radish (Raphanus sativus L.) and green mustard (B. juncea L.) can be utilized as trap crops in the field for this pest. Similarly, the incidence of C. pavonana on cabbage was curtailed by growing Chinese cabbage (B. pekinensis (Lour.) Rupr. cv. Tempest), or flowering green mustard next to cabbage. The population of H. tibialis on cabbage was also considerably reduced when it was grown with radish, Chinese cabbage or mustard as trap crops. Liriomyza spp. population was very low as the introduced parasites effectively suppressed them. Spodoptera litura was attracted to cabbage more than other crucifers. Pydrin (fenvalerate) is effective in controlling this pest. Solenopsis geminata occasionally became a problem in newly transplanted fields during the dry season. Drenching with diazinon controlled this ant. Diamondback moth was a serious problem in one of the trials conducted in 1988. Seasonal variation in occurrence of this pest was evident and it was noted only in the dry season. Information on diamondback moth in terms of host preference and effective insecticides remains to be determined.