A decade of successfull control of pine caterpillar, Dendrolimus punctatus walker (lepidoptera: Lasiocampidae), by microbial agents

Abstract

Dendrolimus punctatus Walker has been one of the most serious pests of the pine trees Pinus luchuensis, P. elliottii and P. massoniana in northern Taiwan. It develops three generations each year. A combination of locally isolated species of fungus ( Isaria farinosa), Bacillus thuringiensis, and a cytoplasmic polyhedrosis virus (CPV) isolated from D. spectabilis Butler in Japan was used to control the pest in different plantations during 1966–1971. The I. farinosa in combination with B. thuringiensis was applied for the first generation larvae (October–March) when it was cool and wet, and temperature and humidity were most suitable for the fungus. CPV and B. thuringiensis were applied in the second (May–June) or third generation (July–August) when conditions were favourable for the development of the virus, Since the applications, yearly observations have been made, and there was no occurrence of the pest until 1982, when outbreaks were seen in some of the plantations, and again in 1983. It is believed that the successful control was due to the microbial agents, and that their effectiveness had lasted for some 10–12 years.