EFFECTS OF CHILLING OF BEMISIA-ARGENTIFOLII (HOMOPTERA, ALEYRODIDAE) INFESTING CABBAGE

Cold temperatures affected the biology of Bemisia argentifolii Bellows and Perring on cabbage both directly and indirectly. Continuous chill ing of 0 degrees C and 4 degrees C significantly increased mortality o f adults and eggs. Variable daily chilling of 0 degrees C for 6 h and then greenhouse conditions for the remainder of the day increased adul t mortality but did not affect egg mortality for the 10 days of exposu re. Prior plant exposure to 0 degrees C resulted in reduced adult B. a rgentifolii preference and increased adult mortality. Previous 0 degre es C and 4 degrees C plant exposure also had an impact on within plant distribution of adults and eggs. On nonchilled and recently chilled p lants, adults and eggs were found on the youngest (highest) leaves. On plants chilled at 0 degrees C and 4 degrees C three and five days bef ore infestation, adults and eggs were found on lower leaves. Lower imm ature mortality was recorded on the nonchilled plants than on the chil led plants.