Influences of Different Host Plants on Biological and Food Utilization of the Cotton Leafworm, Spodoptera littoralis

Abstract

The effects of four host plants, broad bean, cabbage, clover and tomato as foods for Spodoptera littoralis (Lepidoptera: Noctuidae), on certain biological aspects of the insect were studied under laboratory conditions (25 ± 1°C and ≈70% R.H). The results and statistical analysis showed that all of the biological parameters included in the study were affected by the host plants whereas the shortest larval duration (13.2 ± 0.577 days) was recorded for larvae fed on cabbage and the longer (23.3 ± 0.76 days) resulted when larvae fed with tomato. The pupation percentages on tomato leaves were lowest (58.2 ± 1.79 %) and highest pupation was (86.7 ± 1.36 %) when larvae fed on cabbage leaves. Moreover, adult emergence percentages were (80 ± 0.38 %) in tomato and (98 ± 1.36 %) on cabbage. The numbers of eggs oviposited by female S. littoralis were highest on cabbage, followed by those on the broad bean, clover, and lowest on tomato. Based on the nutritional values of testing host plants proved to be effective in reduced development and reproductive capacity of S. littoralis. Also, results proved that cabbage leaves most favorable host for S. littoralis larvae followed by broad bean leaves. While tomato and clover leaves were the relative unsuitable due to the differences in the leaf nutritional quality as mentioned during phytochemical analysis and the high level of amino acid in the hemolymph of larvae fed on cabbage and broad bean leaves.