Bioassay and Life Table Changes in Spodoptera littoralis (Boisd.) Treated with Biocontrol Agents Exposed to Gamma Ray

Abstract

Biocontrol treatments of Bacillus thuringiensis (Kurs.), emamectin benzoate and Spinosad were used singly or exposed to gamma ray doses (120 & 480 Gy) to potentiate its efficacy purposes on Spodoptera littoralis (Boisd.) treated as 4th instars larvae. Also, biological & life table changes were assessed as a result of S. littoralis treated with LC50 of mentioned compounds. Emamectin benzoate treatments, especially emamectin benzoate + 480 Gy had the highly efficacy compound with the least LC50 values on S. littoralis larvae, followed by Spinosad treatments and finally B. thuringiensis treatments that was the least efficacy. Also, emamectin benzoate + 480 Gy than other treatments used had the highly changes in the most biological assessments of S. littoralis treated as 4th instars larvae
with LC50 of the treatments used acts in egg, larval, pupal & moth duration and mortality; addition, no. egg/female, fecundity%, sterility (observed & corrected) and control of hatchability were affected by the same treatment. Moreover, emamectin benzoate +480 Gy compared to other treatments effect on the most life table assessments acts in generation time (T) & doubling time (DT) increasing. Also, net reproductive rate (Ro), intrinsic rate of natural increase (rm), finite rate of increase (erm), female progeny/female (Mx) and its survival rate (Lx) were decreased in S. littoralis treated as 4th instars larvae by LC50 of the same compound compared with other treatments and untreated. So, gamma rays used (120 & 480 Gy) can potentiate its biocides action used especially in emamectin benzoate + 480 Gy treatment that considered the highly changes on efficacy, biological & life table assessments of S. littoralis treated as 4th instars larvae.