Fitness costs and stability of Cry1Ab resistance in sugarcane borer, Diatraea saccharalis (F.)

Document Type

Article

Publication Date

1-1-2014

Abstract

The sugarcane borer, Diatraea saccharalis (F.), is a major target species of transgenic corn expressing Bacillus thuringiensis (Bt) proteins in South America and the U.S. mid-south region. In this study, the fitness of seven insect genotypes of D. saccharalis were assayed on non-toxic diet, which included a Cry1Ab-susceptible strain (SS-2009), two Cry1Ab-resistant strains (RR-43ABC, RR-L5BBC), and four F1 hybrids (F1-R43AmSf, F1-R43AfSm, F1-R5BmSf, and F1-R5BfSm). The F1 hybrids were generated by reciprocal crosses of SS-2009 with RR-43ABC and RR-L5BBC, respectively. Biological parameters measured were neonate-to-pupa survivorship, neonate-to-pupa development time, pupal mass, pupa-to-adult emergence rate, and progeny (neonates) production. The overall performance of the two resistant strains and the four F1 genotypes was either similar or better than SS-2009 for all biological parameters measured, suggesting a lack of fitness costs associated with the Cry1Ab resistance traits in both RR-43ABC and RR-L5BBC. In addition, resistance stability was evaluated by measuring the Cry1Ab susceptibility of RR-43ABC and RR-L5BBC in the absence of selection pressure. Laboratory bioassays showed that larval mortality of the two resistant strains did not significantly increase after selection pressure was removed for 16 generations across all Cry1Ab concentrations assayed. The results provide valuable information on assessing resistance risk and developing effective management strategies for the sustainable use of Bt corn technology. © 2014 Elsevier Inc.

Publication Source (Journal or Book title)

Journal of Invertebrate Pathology

First Page

26

Last Page

32

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