Effect of Oxymatrine 2.4% in some Biological Aspects of Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae)

Abstract

This study was conducted to evaluate the biological effects and the antifeedant effect of pesticide Oxymatrine 2.4% on the larval stage of cotton leaf worm Spodoptera littoralis when the second and fourth instar larvae fed on food treated with concentration 0.5 ,0.75 and 1 ml.Lˉ¹ of pesticide. The results of second larvae instar showed the highest mortality percentage which reached 76% when 1 ml.Lˉ¹ conc. was used. The lowest mortality percentage was 28.3% at the conc. 0.5 ml.Lˉ¹ The mortality percentage reached 34.3% at 1 ml.Lˉ¹ for fourth larvae instar. The results also indicated that the period of larvae growth and pupae were prolonged and decrease in the rate of adult age and the number of eggs laid of adults emerged from treated stages larvae. This study showed that Oxymatrine 2.4% had antifeedant effect against cotton leaf worm and the second instar larvae were the most susceptible, the effect of the pesticide was 70% for the second instar larvae while reached 29.9% for fourth instar larvae at ml.Lˉ¹.