Effect of aerial insecticide spraying on pine wilt disease in central Japan.

To clarify the effect of aerial insecticide spraying on pine wilt disease, pine wilt disease impacts was surveyed in pine stands and the damage evaluated using a logistic model. Eleven quadrats were established randomly in stands with or without aerial spraying. Aerial spraying alone did not entirely prevent the disease. Average annual mortality was lower in stands with aerial spraying than in stands without aerial spraying. Aerial spraying slowed the progress of pine wilt disease, as measured by the disease progress index. The biomass of live pine trees decreased with increased damage in stands without aerial spraying, whereas biomass was maintained in stands with aerial spraying. However, the relative basal area showed that succession of pine forests to forests dominated by other species was accelerated even in stands with aerial insecticide spraying. [ABSTRACT FROM AUTHOR]