| Summary: | A systematic survey of the microbial and invertebrate natural enemies of Phyllophaga spp. was conducted from 1979 to 1981 in 45 localities in southern Quebec. Chronic but low (nonepizootic) rates of biotic regulation were found in all host life stages except eggs. The natural enemies included 36 species of predatory and parasitic insects, 15 mite species, six fungal species, five bacterial species, three different nematodes, one virus, one gordian worm, and one sporozoan. Microorganismal pathogenicities to white grubs were demonstrated by infectivity tests and laboratory bioassays using four methods of inoculation. Field-type microplot studies on the fungus Metarhizium anisopliae and the nematode Mikoletzkya aerivora were undertaken in 1982. The fungus and the nematode showed potential as biological suppressants of Phyllophaga grubs by causing 91% and 68% mortality, respectively. Twenty-seven chemicals were tested as attractants against P. anxia adults in 1981 in four localities in southern Quebec. Hexanoic acid was consistently the most attractive chemical to beetles of both sexes.
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