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Chemical control of Bactrocera cucurbitae in crops biomagnifies toxic residues in fruits and vegetables imposes health-hazard effects on consumers and demands for eco-friendly approaches. Present research assessed the bio-efficacy of Beauveria bassiana, Metarhizium anisopliae, Verticillium lecanii and Bacillus thuringiensis by adult-diet-bioassay at eleven concentrations (1 × 108, 5 × 107, 1 × 107, 5 × 106, 1 × 106, 5 × 105, 1 × 105, 5 × 104, 1 × 104, 5 × 103 and 1 × 103 CFU ml−1) of each entomopathogen against B. cucurbitae at three post-exposure-intervals (PEI) under controlled conditions. The results revealed that the maximum concentration (1 × 108 CFU ml−1) of B. bassiana, M. anisopliae, V. lecanii and B. thuringiensis caused 5.3 to 7.7, 7.4 to 9.2, 5.3 to 6.7 and 5.1 to 11.2 times higher mortality in B. cucurbitae, respectively at 10 d PEI as compared to mortality demonstrated by the same concentration at 3 d PEI. All tested microbial-insecticides induced statistically similar mortality in both male and female B. cucurbitae at each concentration for the same PEI. Correlation coefficient (r) values reveal that concentrations of each microbial-insecticide had a high positive correlation with mortalities of male and female B. cucurbitae [r(B. bassiana) = 0.691 to 0.865, r(M. anisopliae) = 0.643 to 0.849, r(V. lecanii) = 0.508 to 0.886 and r(B. thuringiensis) = 0.591 to 0.812]. Regression-parameters reveal that concentrations of tested microbial-insecticides had significant linear-relationship with and explained significant variability in B. cucurbitae mortality (P < 0.05). At maximum PEI (10 d), B. bassiana exhibited least LC50 (4.10 × 101 to 1.87 × 102 CFU ml−1) and proved highly toxic followed by M. anisopliae (1.16 × 102 to 3.55 × 102 CFU ml−1), B. thuringiensis (2.97 × 102 to 5.92 × 102 CFU ml−1) and V. lecanii (4.50 × 102 to 7.64 × 102 CFU ml−1). In conclusion, B. bassiana incorporated adult-diet proved highly effective against B. cucurbitae followed by M. anisopliae, B. thuringiensis and V. lecanii. Hence, B. bassiana can be recommended for incorporation in bait-traps to develop attract-and-kill technology for B. cucurbitae. [ABSTRACT FROM AUTHOR]

The rice leaf roller or leaf folder, Cnaphalocrocis medinalis (Guenee) (Lepidoptera: Pyralidae), is a serious pest of rice crop in Pakistan. The present study was carried out to evaluate the virulence of the entomopathogenic fungi (EPF) Beauveria bassiana, Verticillium lecanii, and Metarhizium anisopliae against the third instar of C. medinalis larvae. Larvae were exposed to fungi under controlled conditions at the available commercial concentration (1 × 108 conidia ml−1). The results showed 73.33, 57.78, and 74.44% mortality rates in the in vitro assay and 56.67, 41.11 and 52.78% in the greenhouse assay of B. bassiana, V. lecanii, and M. anisopliae, respectively. The maximum mycosis from cadavers of C. medinalis was observed at B. bassiana treatment in the in vitro assay (70%) and in the greenhouse assay (53.78%). The maximum sporulation from C. medinalis cadavers was observed at B. bassiana treatment in the in vitro assay (144.67 conidia ml−1) and in greenhouse assay (96.67 conidia ml−1). These results favor the alternative use of EPF in organic rice production for management of C. medinalis. [ABSTRACT FROM AUTHOR]