The objective of this study was to evaluate the effect of salicylic and tannic acids on some biological aspects of spiny bollworm, Earias insulana including hatching percent, immature stages and mature stages. The study also extended to assess the effect of the same acids on the incubation period, hatching period and hatching percent of eggs of the glassy clover snail, Monacha cartusiana. Survival of the offspring hatched from M. cartusiana eggs treated with these acids has been also investigated. Results indicated that the effect of salicylic acid on E. insulana eggs was more than tannic acid effect. 55% was the highly larval mortality achieved by salicylic acid at1900 ppm. Tannic acid recorded the lowest larval duration 13.5 days at the concentration 1000 ppm. 0.0567 and 0.0457 g were the lowest larval and pupal weight recorded by tannic acid at 2000 ppm. The highly decreasing of pupal duration was observed at the concentration 500 ppm of tannic acid. 45 and 11% were the lowest pupation percent exhibited by salicylic acid at 1900 ppm and tannic acid at 1500 ppm, respectively. On the other hand, Tannic acid prevents egg laying at 2000 and 1500 ppm. The two acids decreased significantly the oviposition period, adult longevity, fecundity and the hatching percent. Regarding to the biological parameters of M. cartusiana snail, incubation and hatching periods increased by increasing the concentrations of the two acids. While, hatching percent of eggs decreased by increasing the concentrations of each acid. Salicylic acid at 2375 ppm gave the lowest hatching of eggs 43.88%. There was a reduction on survival of the offspring hatched from treated eggs by each tested acid. 65.02 % represent the lowest survival of the offspring snails achieved by salicylic acid at 2375 ppm.