A seed mixture increases dominance of resistance to Bt cotton in Helicoverpa zea

Thierry Brévault, Bruce E Tabashnik, Yves Carriere

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

Widely grown transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt) can benefit agriculture, but adaptation by pests threatens their continued success. Refuges of host plants that do not make Bt toxins can promote survival of susceptible insects and delay evolution of resistance, particularly if resistance is inherited as a recessive trait. However, data have been lacking to compare the dominance of resistance when Bt and non-Bt seeds are planted in random mixtures versus separate blocks. Here we report results from greenhouse experiments with transgenic cotton producing Bt toxin Cry1Ac and the bollworm, Helicoverpa zea, showing that the dominance of resistance was significantly higher in a seed mixture relative to a block of Bt cotton. The proportion of larvae on non-Bt cotton plants in the seed mixture was also significantly higher than expected under the null hypothesis of random distribution. In simulations based on observed survival, resistance evolved 2-to 4.5-fold faster in the seed mixture relative to separate blocks of Bt and non-Bt cotton. These findings support previous modelling results indicating that block refuges may be more effective than seed mixtures for delaying resistance in pests with mobile larvae and inherently low susceptibility to the toxins in Bt crops.

Original languageEnglish (US)
Article number9807
JournalScientific Reports
Volume5
DOIs
StatePublished - May 7 2015

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Bacillus thuringiensis
Zea mays
Seeds
Larva
Gossypium
Agriculture
Insects

ASJC Scopus subject areas

  • General

Cite this

A seed mixture increases dominance of resistance to Bt cotton in Helicoverpa zea. / Brévault, Thierry; Tabashnik, Bruce E; Carriere, Yves.

In: Scientific Reports, Vol. 5, 9807, 07.05.2015.

Research output: Contribution to journalArticle

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