Journal of Economic Entomology (1999) 92, 547-550

Fangneng Huang, Lawrent L. Buschman and Randall A. Higgins (1999)
Susceptibility of different instars of European corn borer (Lepidoptera : Crambidae) to diet containing Bacillus thuringiensis
Journal of Economic Entomology 92 (3), 547-550
Abstract: The relative susceptibility of different instars of the European corn borer, Ostrinia nubilalis (Hübner), to a commercial formulation of Bacillus thuringiensis Berliner subsp. kurstaki, Dipel ES, was determined using diet incorporation. European corn borers exposed to Dipel during the 1st instar were much more susceptible than were older larvae. No significant differences in susceptibility were found among 3rd, 4th, and 5th instars at doses of 0.03-0.81 ml of Dipel per kilogram of diet. At high concentrations (2.43 ml/km of diet), 5th instars had significantly lower mortality than did 3rd or 4th instars. The LC₅₀ and LC₉₀ of the 5th instars were 98.1- and >168.2-fold higher, respectively, than those of 1st instars. These findings should be accounted for during the development of a resistance management strategy for the use of B. thuringiensis toxin as a microbial insecticide and possibly, for Bt-expressing transgenic corn. Differential susceptibility of different instars of European corn borer to B. thuringiensis suggests that the "ultra high-dose" or "high-dose" resistance management strategy should be defined in terms of the largest and the least susceptible stage, because larvae may have opportunities to grow and develop on non-Bt-corn or alternate hosts before they attack the Bt-corn plants.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Fang Neng Huang, Lawrent L. Buschman

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Ostrinia nubilalis
Bacillus thuringiensis var. kurstaki (entomopathogen)	Ostrinia nubilalis