Environmental Entomology (1989) 18, 816-821

Leah S. Bauer and Gerald L. Nordin (1989)
Response of spruce budworm (Lepidoptera: Tortricidae) infected with Nosema fumiferanae (Microsporida) to Bacillus thuringiensis treatments
Environmental Entomology 18 (5), 816-821
Abstract: Disease in spruce budworm, Choristoneura fumiferana (Clemens), caused by the microsporidian Nosema fumiferanae (Thomson), increased larval susceptibility to mortality by Bacillus thuringiensis (Berliner) treatments compared with larvae free of N. fumiferanae disease. The median lethal concentration (LC₅₀) of B. thuringiensis, as determined by the diet incorporation bioassay method, was significantly lower for larvae infected transovarially with N. fumiferanae, but the similar slope obtained for initially healthy larvae indicated an independent and additive interaction. The median lethal time (LT₅₀) for B. thuringiensis was shortest for the group diseased with N. fumiferanae. Results from separate and sequential oral treatments (horizontal transmission) of both microorganisms at fixed physiological stages support the findings from the transovarial studies. It also was determined that N. fumiferanae-free larvae surviving B. thuringiensis treatments were more susceptible to mortality from subsequent inoculations with N. fumiferanae than were larvae not previously exposed to B. thuringiensis.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
environment/habitat manipulation
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Choristoneura fumiferana
Bacillus thuringiensis (entomopathogen)	Choristoneura fumiferana
Nosema fumiferanae (entomopathogen)	Choristoneura fumiferana