Toxic and repellent potentials of spinosad against Cryptolestes pusillus (Schon.) (Coleoptera: Cucujidae)

Abstract

The contact and gustatory effects of spinosad on the mortality and repellency of Cryptolestes pusillus (Schon.) were conducted under laboratory conditions. Spinosad at 0.32 l/g caused lowest mortality (16.67±1.67% of 2nd instar larva of C. pusillus in wheat after 24h and highest mortality (59.14±1.65%) was observed at 1.25 l/g in wheat after 72 h exposure. The LC50 value was 0.11 l/g in wheat after 72 h, which indicated that spinosad is highly toxic against the 2nd instar larvae of C. pusillus. In case of 4th instar larvae highest mortality (58.12±3.45%) were observed at 1.25 l/g concentration but lowest 10.00± 2.10 after 24 h exposure. The highest mortality was observed (40.00±2.88%) in adults. The different doses (1.25, 0.63, 0.32, 016 and 0.08 l/ml) of spinosad showed repellent activities against adults of C. pusillus. All the doses of spinosad offered 0.1% level of significance (P<0.01). Spinosad used in this experiment have great potential in the control of C. pusillus which is important from the Integrated Pest Management and the Global Environmental Protection point of views.