Role of Feeding Stimulants in Increasing the Efficacy of Bacillus thuringiensis versus Spodoptera littoralis (Lepidoptera: Noctuidae)
Salama, Hussein Samir; Foda, Salah; Sharaby, Aziza
Investigations have been made to find eliciting feeding materials of the lepidopterous cotton pest Spodoptera littoralis (Boisduvalle 1883) and to determine the feasibility of using these materials to increase the efficacy of Bacillus thuringiensis var entomocidus HD-635 vs this species. Extracts of some host plants and their volatile fractions proved to be active feeding stimulants to the tested species and potentiated the effect of B. thuringiensis when combined with it. Some components of the cotto volatile oil led to a significant increase in the potency of the bacterial preparation. Coax, molasses, soybean flour, cottonseed flour, sucrose and its combinations with cotton leaf powder or its extracts can be used as adjuvants to increase the efficacy of B. thuringiensis. Among the sugars, sucrose was highly stimulating to the tested species where it result in increased ingestion of the bacterial preparation and subsequent higher larval mortality.