The ecology of Paecilomyces farinosus in two balsam fir forests infested with spruce budworm

The occurrence of Paecilomyces farinosus and other microfungi on litter was monitored in two balsam fir forests infested with spruce budworm to determine the possible role of this fungus as a saprophyte in these forests. The microfungi on the fir litter were similar to those found on other conifers. Paecilomyces farinosus, however, was very abundant, and its abundance increased on the litter after it fell to the ground. An apparent correlation between the abundance of the fungus and the population of spruce budworm suggests that opportunistic parasitism may positively affect the abundance of P. farinosus. Key words: Paecilomyces farinosus, entomopathogens, balsam fir, litter, microfungi.