Field Efficacy of Nuclear Polyhedrosis Virus for Protection of Teak against the Defoliator, Hyblaea puera Cramer (Lepidoptera:Hyblaeidae)

In the year 1993, a 100 tree plot in a 17 year old teak plantation at Nilambur in Kerala was experimentally protected from Hyblaea puera Cramer, a serious defoliator of teak plantations, using a naturally occurring baculovirus (HpNPV) reported earlier from this pecies. During the year, there were four major peaks of defoliator infestation from March to June. One-time foliar application of a crude preparation of HpNPV at the rate of 1x10⁵ POB/ml of the spray fluid, at the earliest sign of each infestation, gave 70-76 per cent protection of foliage during the first two infestations. A reduced foliage protection of 33-43 per cent obtained during the third and fourth infestations was attributable to occurrence of rain soon after application of the spray. In protected trees, the basal area increment was enhanced by 41 per cent, indicating the efficacy of HpNPV as a biocontrol agent against the teak defoliator.