Review on microbial control of insect pests in forests in Japan

In Japan, two different serious defoliators were controlled by viruses:Dendrolimus spectabilis using cytoplasmic polyhedrosis virus andLymantria fumida using cytoplasmic and nuclear polyhedrosis viruses. For controllingD. spectabilis, good results were obtained when the spraying was done against old larvae of intermediate population density. AgainstL. fumida, a mixed suspension of native nuclear and cytoplasmic polyhedrosis viruses was sprayed at the early stage. The epizootic was initiated earlier than being supposed, and the population collapsed.