EFFECTS OF ANTIBACTERIAL MATERIALS ON BEMISIA-ARGENTIFOLII (HOMOPTERA, ALEYRODIDAE) OVIPOSITION, GROWTH, SURVIVAL, AND SEX-RATIO

Whiteflies and other homopterous insects contain endosymbiotic organis ms that are essential for their development and reproduction. Reductio n or elimination of the endosymbiotic organisms in insects by antibiot ic therapy results in reduced insect growth, death, or lack of reprodu ction. Thus, endosymbionts provide a potential target for insect contr ol with systemic antibacterial materials, or transgenic plants that pr oduce antibacterial proteins. We investigated the effects of various a ntibiotics, with different ranges of activity and modes of action, on the whitefly Bemisia argentifolii Bellows & Perring (also known as Bem isia tabaci B biotype) oviposition rate, growth, survival, emergence a s adults, and sex ratio. The materials tested were oxytetracycline hyd rochloride, rifampicin, penicillin, ampicillin, lysozyme, and chloramp henicol. Method of application (feeding on diet or excised leaves) sho wed similar effects on adults or nymphs. Of the materials tested, thos e that had significant negative effects on growth and development of w hiteflies (tetracycline and rifampicin) interfere with bacterial prote in synthesis. Those materials that primarily attack the bacterial cell walls or cell membranes (penicillin, ampicillin, and lysozyme) did no t have any significant effect on growth and development. Treatments wi th antibacterial materials had no significant effect on oviposition ra tes of adults or the sex ratio of their offspring. Delays in developme nt, and reduction in the percentage of offspring emerging as adults pr ovide ample evidence that antibacterial materials have potential role in management strategies against both adult and immature stages of whi teflies.