Efficacy of the entomopathogenic fungus,Paecilomyces fumosoroseus(Wise) Brown and Smith (Ascomycota: Hypocreales) againstGeotrogus deserticola(Coleoptera: Melolonthidae)

Abstract

Different conidial concentrations of isolate P 83 of Paecilomyces fumosoroseus ranging from 1 × 106 to 1 × 1010 conidia/ml were injected through the anus of geotrogus deserticola on the 2nd and 3rd instars larvae. The larval mortality caused by fungal infection differed significantly and increased with increasing conidial concentrations. Results revealed 100% mortality of 2nd instar larvae at 1 × 1010, 1 × 109, and 1 × 108 conidia/ml and the lower mortality 93.33% was obtained at 1 × 106 conidia/ml, 6-day post treatment. For the 3rd instar larvae the higher mortality (93.33%) was noticed at 1 × 1010 and the lower (53.33%) at 1 × 106 conidia/ml 8 day of post inoculation. The estimated LC50 was 4.73 × 104 and 2.13 × 105 conidia/ml and the LT50 values was 3, 64 days and 3, 90 days respectively for the 2nd and the 3rd instar larvae treated.