Abstract

Based on systematic field observations, it is shown that in teak plantations, the first noticeable event in the chain of events leading to widespread outbreak of the caterpillar, Hyblaea puera (Lepidoptera, Hyblaeidae) is the sudden occurrence of fairly high-density, tree-top infestations in small, discrete patches. This follows a long period of near-absence of the insect population during the leaf-fall and early flushing period, and appears to coincide with the first pre-monsoon showers. These tree-top infestations cover small patches (0. 5 to 1. 5 ha) and are widely separated in space. This transitional stage between very sparse endemic populations and high-density outbreak populations is followed by further high-density infestations which are still confined to a few, but larger, patches. Wide-spread outbreaks covering large extent of plantations occur in the next phase. The evidences indicate that H. puera population outbreak is of the ""eruptive"" type