Attempts at controlling Teak Defoliator (Hyblaea puera Cramer, Lepidoptera, Hyblaeidae) with the entomopathogenic fungus, Metarhizium anisopliae (Metsch.): laboratory, nursery and field trials

Defoliator pests often cause severe damage to commercially valuable timber trees, such as teak, grown in plantations, affecting the quality and quantity of the wood produced. Twenty-five isolates of an entomopathogenic fungus, Metarhizium anisopliae (Metsch.), derived from different forest habitats were tested for their efficacy against the Teak Defoliator, Hyblaea puera Cram. The median lethal concentration (LC50) for the isolates ranged from 0.65 to 947.41 x 10(5) conidia mL(-1). Four isolates, viz. MIS2, MIS19, MIS7 and MIS1, were promising, having low LC50 values. A median lethal time (LT50) of 3.8d was recorded for the isolates MIS2 and MIS7 when the moth larvae were exposed to a spore load of 10(7) conidia mL(-1). Formulations composed of MIS2 + MIS7 + 0.5% Pongamia pinnata seed oil and MIS2 + MIS7 proved to be superior against the Teak Defoliator, causing 94.73% and 93.93% mortality, respectively. Application of the formulation MIS2 + MIS7 + 0.5% P.pinnata oil resulted in 63.6% and 56.2% reduction in infestation in nurseries and plantations, respectively, while the formulation MIS2 + MIS7 recorded 56.18% and 51.60% reduction. Our results indicate that M.anisopliae formulations could be an effective means of managing Teak Defoliator in plantations, particularly when combined with P.pinnata oil.