Efficacy of Indigenous Entomopathogenic fungi Beauveria bassiana Isolate for the Control Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae) under Laboratory Conditions

Abstract

Spodoptera littoralis is a serious threat to tomato production worldwide as it can cause yield losses. The farmers used to use synthetic chemical insecticides to control this pest, which unfortunately selects resistant populations and entails public health risks. The aim of this study was to evaluate of indigenous entomopathogenic fungi Beauveria bassiana isolate against different stages of S. littolars life. Results show high significant differences between the three concentrations of suspensions and fungi exudates of B. bassiana in addition differences among time of exposure on ratio of eggs hatching of S. littoralis the high rate of affected of B. bassiana suspension registered at concentration of 1×108 and at concentration 75% of B. bassiana exudates it was reached 32.28% and 34.15% respectively. The study showed that the mortality on 1st and 6th instar larvae of S. littoralis increased as concentration of fungi exudates of B. bassiana increased, it had been 20.51%, 24.65%and 33.45% at concertation 25%, 50%and 75% on 1st instar and reached 3.33%,7.78% and 12.67% on 6th instar of S. littoralis larvae respectively. Moreover suspension fungi of B. bassiana superior at the concentration 1×10 8conidia/1ml of distilled water in the mortality of 1st and 6th instar of S. littolaris larvae with a mortality rate 35.41% and 15.37% respectively.the results showed eggs and 1st instar of of S. littolaris larvae more sensitive to suspensions and fungi exudates of B. bassiana than the 6th instar.