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The operational use of Bacillus thuringiensis subsp. kurstaki (Btk) to control the western spruce budworm in the mountainous terrain of British Columbia, Canada, gives variable results at the registered dose of 30 BIU ha − 1 in 2.4 L ha − 1. Btk (Foray 48B®, 60 BIU ha − 1 in 4.8 L ha − 1) was applied experimentally in 1996 over 150-ha of western spruce budworm-infested Douglas-fir forest to determine if increasing both the dose and volume of Btk applications gives more uniform and effective control. We sampled native caterpillars on the shrub Ribes cereum Douglas in this and a similar, untreated area 2 km away from 1996 to 1998 to assess the impact of this high dose and volume Btk application on non-target Lepidoptera. The numerically dominant lepidopteran species were Euhyponomeutoides gracilariella Busck (52%) and Gelechia ribesella Chambers (32%). The remaining 16% of the guild was comprised of numerous sparsely distributed species. Total larval abundance was significantly lower on plants that were spr...

A non-toxic phase separation method was developed for microencapsulation of inoculum used in biological control. Aqueous sodium alginate or gelatin and agar was mixed with inocula of various biopesticides and emulsified in a mixture of corn oil, n-hexadecane, and lecithin. Gelatin and agar globules gelled in the emulsion; alginate globules gelled after settling into a lower phase of aqueous CaCl2. A layer of gelatinous material thus surrounded the inoculum as 'capsules'. Mixing with n-hexadecane reduced the specific gravity and surface tension of the oil, allowing aqueous extraction of the capsules. Successful extraction of alginate capsules depended upon lecithin (>0.17%), n-hexadecane (>30%), and CaCl2 (>0.01 M) concentrations. Alginate-encapsulated macroconidia of Fusarium avenaceum caused 23±3% leaf area damage to seedlings of marsh reed grass, versus 4±3% for unformulated controls. In green foxtail seedlings, gelatin and agar-encapsulated conidia of Bipolaris sorokiniana caused 21.3 vs. 7.9 ...

Pyemotes barbara, n. sp., is illustrated and described. This species is parasitic on pupae of Barbara colfaxiana (Kearfott), one of the important cone and seed pests of Douglas-fir, Pseudotsuga menziesii (Mirbel) Franco. The Pyemotes mite considered here is a candidate for the biological control of forest insects.