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Resistance and behavioural response of Plutella xylostella (Lepidoptera: Plutellidae) populations to Bacillus thuringiensis formulations
Author(s) -
Zago Hugo B,
Siqueira Herbert ÁA,
Pereira Eliseu JG,
Picanço Marcelo C,
Barros Reginaldo
Publication year - 2014
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.3600
Subject(s) - plutella , plutellidae , bacillus thuringiensis , lepidoptera genitalia , diamondback moth , biology , toxicology , insecticide resistance , resistance (ecology) , larva , insect , pesticide resistance , horticulture , agronomy , botany , pesticide , bacteria , genetics
BACKGROUND Insecticide resistance is probably the major cause of control failure of Plutella xylostella (L.) in Brazil. In most production regions, the use of chemicals has been the prevalent method of control, with reduced efficacy through cropping seasons, even for the most recent use of products based on Bacillus thuringiensis ( Bt ). The current status of the resistance to these products was assessed, as well as the behavioural response of P. xylostella populations to Bt sprays . RESULTS Most populations of P. xylostella were resistant to Bt products, particularly to Xentari® WDG (2–54‐fold). Differences in walking characteristics of larvae were variable for most populations, for both Dipel® WP and Xentari® WDG , but not associated with resistance. Most females preferred to lay eggs on untreated surfaces and showed a reduced proportion of oviposition on treated surfaces that only correlated with resistance to Dipel® WP ( r = −0.74, P = 0.02) . CONCLUSION Broad and indiscriminate use of Bt ‐based products has selected Brazilian P. xylostella populations to resistance. Larval movement appears to be a resistance‐independent mechanism. Most populations of P. xylostella preferred to lay eggs on Bt ‐free surfaces, which might be a result of growers' practice of spraying the cabbage head. Reduced oviposition on treated surfaces correlated with physiological resistance, suggesting a behavioural response among the Bt ‐resistant colonies to Dipel® WP . © 2013 Society of Chemical Industry