Ovicidal action of different fungal pathogens against two spotted spider mite, Tetranychus urticae (Koch) under laboratory conditions

Bioassay studies were performed with ten different fungal isolates of six species against two spotted spider mite, Tetranychus urticae. Among different formulations, Hirsutella thompsonii caused significantly higher mortalities of 61.1, 35.8 and 22.1 per cent at conidial concentrations of 971, 196 and 36 conidia mm^-2, respectively. At a conidial concentration of 1457 conidia mm^-2, Beauveria bassiana isolate Bb101 caused significantly higher mortality rate of 46.9 per cent followed by B. bassiana isolate B2 (36.1%) and Cladosporium cladosporioides isolate Cc101 (32.1%). Based on the probit estimates, H. thompsonii was found to exert high ovicidal activity with the lowest LC₅₀ of 674 conidia mm2 against T. urticae eggs.