Abstract: Studies on three different ways of applying Beauveria bassiana against masson pine caterpillar (Dendrolimus punctatus) show that the caterpillar populations in three forest farms were all suppressed at low levels in4 successive years, but the population dynamics was completely different.In Magushan Forest Farm, with the way of inumdatively applying B.bassiana primarily and chemical insecticides alternatively, the average population density was 3.16±4.94 per tree, with a sharp fluctuation.In Daigongshan Forest Farm, however, with the way of long term inoculative application of B.bassiana, the population was at very low level, with an average density of 0.09±0.14.In Jinsishan Forest Farm, small area epicenters of caterpillars were accurately detected and treated with chemicals primarily and with B.bassiana alternatively, and the average density was 1.45±2.29, with occasionally reaching control standard.Investigation on community composition revealed that from Magushan to Jinsishan to Daigongshan, the total individual number of animal and entomogenous fungi was decreased, while the total species number, the ratio of total species number to total individual number, the species ratio of natural enemies to pests, the individual number ratio of natural enemies to pests, and the community diversity indices were all increased, indicating a tendency of commumity diversity getting richer, food chain getting more complicated, and community stability and ability of natural control of pest getting stronger.Furthermore, the principal component analysis shows that from Magushan to Jinsishan to Daigongshan, the evolution of animal and entomogenous fungi communities became clearer in temporal series, tended to stable, and with a stronger auto regulation ability.

Key words: Beauveria bassiana, Dendrolimus punctatus, Appliction strategy, Inundative application, Inoculative application