Insecticidal Activity of Some Wild Plant Extracts Against Cotton Leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae)

Abstract

The biological and phytochemical studies of four Egyptian wild plants/weed were studied against Spodoptera littoralis. M. senegalensis had highly significant antifeedant activity on the 3rd instar larvae of S. littoralis followed by Cl. amblyocarpa and S. argel, with 95.52, 45.23 and 32.12%, respectively. Larval mortality was relatively higher in case of M. senegalensis and S. argel. Extract of Cl. amblyocarpa was the only extract which causes malformation to pupae of S. littoralis. The highly pupal mortality was recorded in case of M. senegalensis extract (80%). The most effective extracts on reduction of pupal weight were Cl. amblyocarpa and A. setifera. The adult emergence percentage in case of M. senegalensis was 20% as compared to 95% in the control and all females moths resulting were deformed and all died before oviposition. The lowest number of eggs was observed in case of A. setifera extract and the eggs did not hatch. A. setifera and M. senegalensis possess both behavioural effects and post ingestive toxicity on the developmental stages of S. littoralis. A. setifera extract had the superior ovicidal activity on the viability of S. littoralis egg masses aged 72, 24 and 48 h, with 72.22, 39.77 and 31.82% reduction, respectively. The longer the post treatment period, the lower the bioefficacy of plant extracts against the target insect. M. senegalensis extract showed high latent mortality by the lapse of time, where 88% mortality occurred after 15 days from treatment at initial time and the residual effect remained for 5 days with 18% mortality after 15 days at 5 days post treatment. The lowest effective extract was S. argel which was effective for 3 days after treatment.