BEMESIA ARGENTIFOLII (HOMOPTERA, ALEYRODIDAE) - HOST PREFERENCE AND FACTORS AFFECTING OVIPOSITION AND FEEDING SITE PREFERENCE

Bemisia argentifolii Bellows Er Perring preferred cantaloupe, Cucumis melo, var. cantalupensis L., to cotton, Gossypium, hirsutum L., brocco li, Brassica oleracea var. botrytis L., and lettuce, Lactuca sativa va r. capitata L., in 1992 and 1993 in field and greenhouse studies. In t he absence of cantaloupe, B. argentifolii preferred cotton to broccoli and lettuce, respectively. More eggs and fewer nymphs were found on b roccoli than on cotton in the field. Differences in relative abundance of vascular bundles per unit of leaf area among the four plant specie s may partly account for differences in oviposition site selection. Va scular bundle volume per unit of leaf tissue volume was 50% greater in cantaloupe than in cotton and broccoli, which in rum had significantl y greater volumes than lettuce. Field studies showed that most B. arge ntifolii on cotton and cantaloupe leaves were found on lower leaf surf aces. Distances from upper and lower leaf surfaces to the nearest vasc ular bundles in cotton leaves were 131 and 60 mu m, respectively. This distribution favors oviposition and feeding on the lower surface of a leaf. Leaf structure, positive effect of gravity, and negative effect of light affected oviposition site preferences in laboratory studies.