INDUCED STERILITY IN GREENHOUSE-WHITEFLY (HOMOPTERA, ALEYRODIDAE) TREATED WITH GAMMA-RADIATION

A series of experiments have been carried out to establish the optimum dosage required for the radiosterilization of adults of Trialeurodes vaporariorum Westwood (Homoptera: Aleyrodidae) to be used for the ster ile insect technique. Experimental data have shown that females are mo re radiosensitive than males at the 50-60 Cy dose range. In fact, full female sterility has been achieved with the dose of 50 +/- 5% Cc Male s, treated with this dose, preserved <1% of the capacity to fertilize eggs. They became completely sterile at 60 +/- 5% Cv. High levels of m ortality (up to 35%) have been found in eggs laid by females mated wit h irradiated males. This shows that all irradiated males preserved a r emarkable sperm transfer capacity and competitiveness resulting in egg fertilization but not in embryo development. The treatment with the 2 tested doses did not affect insect longevity untie; laboratory condit ions. Considerations regarding the choice of the most appropriate radi osterilizing dose for the autocidal technique are discussed.