ANTIBIOTIC OXYTETRACYCLINE INTERFERES WITH BEMISIA-TABACI (HOMOPTERA, ALEYRODIDAE) OVIPOSITION, DEVELOPMENT, AND ABILITY TO INDUCE SQUASH SILVERLEAF

The B-biotype of the sweetpotato whitefly, Bemisia tabaci (Gennadius), is associated with squash silverleaf disorder, which is of unknown etiology. Immature white-flies contain paired oval mycetomes composed of large cells (mycetocytes) hypothesized to contain symbiotic microorganisms. Treatment of B. tabaci females with an antibiotic (oxytetracycline hydrochloride) delivered through root treatments of host plants adversely affected adult oviposition and growth and development of offspring, and reduced mycetome size and the number of microorganisms in mycetocytes. These results suggest that microorganisms in the mycetomes of whiteflies are symbiotic in nature, as reported in other homopterans. Treating adult females with oxytetracycline reduced the ability of their offspring to induce symptoms of squash silverleaf in zucchini (Cucurbita pepo L.).