The treatment of different developmental stages and adults of Z. paravittiger with precoceneI failed to produce any precocious metamorphosis, but it definitely proved to be toxic at very low doses to eggs, first instar and second instar and showed an antigonadotrophic effect when adults were topically treated. The ID50 concentrations for emergence were 0.076, 0.005, 1.00, 1000 and 90 ppm for egg, first instar, second instar, third instar and pupae, respectively. The adult longevity and fecundity was reduced even when adults were treated with 0.1 ppm concentration of precoceneI in 1 μl of acetone.
