Entomopathogenic Fungal Screening against Two Spotted Spider Mites, Tetranychus urticae Koch in Tomato and Broad Mite, Polyphagotarsonemus latus (Banks) in Chilli

Abstract

Background: Entomopathogenic fungi are microorganisms that specifically infect and often kill insects and other arthropods. Most are non-pathogenic to plants and relatively non-toxic to humans and animals. Use of fungal entomopathogens can be an alternative to insecticides and could help in bio-intensive pest management. The current study aimed to study the pathogenicity of entomopathogenic fungal isolates against two Spotted Spider Mites, Tetranychus urticae Koch in tomato and broad Mite, Polyphagotarsonemus latus (Banks) in chilli. Methods: An extensive survey for the natural occurrence of entomopathogenic fungi on insects and mites was made in different agro climatic regions of Tamil Nadu during 2013 and 2014. Survey revealed the occurrence of two entomopathogenic fungi viz., Beauveria bassiana (Balsamo) Vuillemin and Metarhizium flavoviride Gams and Rozsypal var. minus. Laboratory experiment was conducted to evaluate the pathogenicity of fourteen isolates of Beauveria bassiana, Metarhizium anisopliae and Lecanicillium lecanii against Tetranychus urticae and Polyphagotarsonemus latus. Result: In opposition to T. urticae, the Beauveria bassiana isolate Bb 112 showed the highest toxicity of all the other isolates tested, with low LC50 value of 0.6 x106 spores ml-1 and LT50 of 92.60h. Against P. latus, Bb 112 had high virulence with low LC50 value of 0.3x106 spores ml-1 and LT50 value of 92.32h. Hence, there is potential for use of entomopathogenic fungi in the field conditions as an alternate control method in combating the insect pests and other arthropod pests since they are considered natural mortality agents and are environmentally safe.