Resistant cabbage cultivars change the susceptibility of Plutella xylostella to Bacillus thuringiensis
1 Laboratory studies demonstrated that the susceptibility of larvae of the lepidopteran crucifer pest Plutella xylostella to the insect pathogen Bacillus thuringiensis (Bt) was influenced by the host plant.
2 Larvae reared on the resistant cabbage cultivars Minicole F1 and Red Drumhead were significantly more susceptible to Bt (the LC50 fell to one half) than larvae fed leaves of susceptible cultivars.
3 However, a third resistant cultivar, Aquarius F1, had no synergistic effect on Bt-related mortality.
4 Actual uptake of Bt was monitored in the bioassays, as a preliminary experiment showed that the plant resistance reduced consumption of Bt-treated leaf discs. However, differences in feeding rate did not explain the observed differences in mortality.
Document Type: Research Article
Affiliations: Department of Horticulture and Landscape, University of Reading, Whiteknights, Reading, RG6 6AS, U.K.
Publication date: 2000-02-01