The teak defoliator, Hyblaea puera (Lepidoptera, Hyblaeidae) is a serious pest of teak plantations in India. In the year 1993, a 100-tree plot of a 17-year old teak plantation at Nilambur in Kerala, Southern India was experimentally protected from this insect using a crude preparation of a naturally occurring Nuclear Polyhedrosis Virus (NPV) reported earlier from this species. There were four major peaks of infestation by the pest from March to June, followed by a minor peak in July. One-time foliar application of NPV at the rate of 1 x 105 PIB/ml of the spray fluid, at the earliest sign of infestation (larval instars 12), gave 70 to 75% protection during the first two infestations and 25 to 40% protection during the third and fourth infestations. The reduced effectiveness of NPV in the latter case was attributable to occurrence of rain, which may have caused wash off of the spray fluid. The protected trees gained about 40% additional basal area increment.
During the course of this study, methods were also standardised for monitoring the pest populations to facilitate timely application of control measures. The results showed that it is feasible to use NPV to control teak defoliator infestations; further developmental work is necessary to formulate the NPV for field application.
Key words: teak defoliator, Hyblaea puera, Nuclear Polyhedrosis Virus, population monitoring.
Correspondence: V.V. Sudheendrakumar, Division of Entomology, Kerala Forest Research Institute, Peechi-680 653, Kerala, India
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