Influence of the nutritional state of Triatoma infestans over the insecticidal activity of DDT.

1. The influence of nutritional state over topical insecticidal activity of DDT in nymph II of Triatoma infestans was analyzed. 2. DDT LD50 for starved nymph II was more than 150 micrograms/insect, while for nymph II fed to repletion on artificial feeder, was 0.79(0.50-3.13) micrograms/insect and a similar result was obtained for nymph II fed on pigeons (1.09(0.36-7.55) micrograms/insect). 3. A very slow penetration rate of 14C-DDT was obtained in non fed insects (4.4% penetrated 46 hr after treatment) in correspondence with 0% of mortality. 8.5% of 14C-DDT was not recovered from the cuticle 2 hr after topication of fed nymph in correspondence with a 100% of mortality at 24 hr.