Teak (Tectona grandis L.), known as the “king of timber”, is a valuable timber tree species in India (Roychoudhury and Dadwal 2010). It has been recognized for centuries as the finest hardwood in the world. It is a primary high-value wood used in furniture manufacture, and the ever-increasing need for teak timber has resulted in the establishment of large scale plantations both within and outside its range of natural distribution (Javaregowda and Naik 2007a). The most important lepidopteran defoliators, which cause defoliation in teak plantations throughout the tropics, are Teak Defoliator, Hyblaea puera Cramer (Hyblaeidae) and Teak Skeletonizer, Paliga machoeralis Walker (Pyralidae) (Tewari 1992). Hyblaea puera is the most widespread and serious pest in both plantations and natural forests, with as many as 14 generations per year (Beeson 1941). Defoliation does not kill the trees, but does lead to substantial timber loss (Nair 1988). Defoliation by H. puera in plantations four to nine years old was reported to cause about 44% volume increment loss of the trunk (Nair and Mohandas 1996). The larvae directly retard girth increment, reduce timber quality by forking, cause death of the leading shoot and result in formation of epicormic branches (Vongxomphou 2001).

With the current interest in addressing environmental pollution and developing integrated control strategies for the management of Teak Defoliator, H. puera, attention is now mainly focused on the use of microbial insect pathogens (Javaregowda and Naik 2008a). The entomopathogenic fungus Metarhizium anisopliae is one among the most exploited hyphomycetes fungi employed in insect pest management. It is a promising agent for controlling insect pests because of its wide geographical range, and its vast spectrum of pathogenicity and infectivity (Zimmermann 2007).

This investigation was focused on determining the potential of M. anisopliae for controlling H. puera. A laboratory bioassay of 25 isolates of M. anisopliae was initially conducted. Two promising isolates, MIS2 and MIS7 and Pongamia pinnata oil, individually and in different combinations were evaluated. Two promising combinations were further tested in nurseries and plantations to identify a better formulation for management of H puera infestation in teak plantations.