First Record of Natural Occurrence of Cladosporium cladosporioides (Fresenius) de Vries and Beauveria bassiana (Bals.-Criv.) Vuill on Two Spotted Spider Mite, Tetranychus urticae Koch from India

摘要

A survey for natural occurrence of entomopathogenic fungi of two spotted spider mite Tetranychus urticae Koch was made in Coimbatore District of Tamil Nadu, India during 2009. Occurrence of two entomopathogenic fungi viz., Cladospoirum cladosporioides (Fresenius) de Vries to the tune of 75.25, 87.00 and 96.75% and Beauveria bassiana (Bals.-Criv.) Vuill to the tune of 7.50, 12.00 and 5.25% were recorded on T. urticae infesting cowpea, red gram and okra, respectively. Both the fungal isolates were assessed for their pathogenicity against the spider mite, T. urticae and the papaya mealybug, Paracoccus marginatus Williams and Granara de Willink commonly occurring on okra and cotton, using leaf disc bioassay. The results revealed that the fungus, C. cladosporioides was more effective followed by the B. bassiana against two spotted spider mite and for mealybug, B. bassiana was found to be more effective. C. cladosporioides and B. bassiana recorded the LC50 values of 4.30x106 and 5.27x106 conidia mL-1 with LT50 values of 63.80 and 110.30 h, respectively against T. urticae . Against P. marginatus , C. cladosporioides and B. bassiana recorded the LC50 values of 5.20x107 and 3.60x107 conidia mL-1 with LT50 values of 191.04 and 176.64 h, respectively. This is the first record on natural infection of T. urticae by C. cladosporioides and B. bassiana in Tamil Nadu, India.