Spider mite infestations reduce Bacillus thuringiensis toxin concentration in corn leaves and predators avoid spider mites that have fed on Bacillus thuringiensis corn. (17th March 2014)

• Record Type: Journal Article
• Authors: Prager, S.M.; Martini, X.; Guvvala, H.; Nansen, C.; Lundgren, J.
• Is Part Of: Annals of applied biology. Volume 165:Number 1(2014)
• Page Start: 108
• Page End: 116
• Publication Date: 2014-03-17
• Subjects: Crop science -- Periodicals; Plants, Protection of -- Periodicals; Crops -- Ecology -- Periodicals; 630
• DOI: 10.1111/aab.12120
• Languages: English
• ISSNs: 0003-4746

Abstract

<abstract abstract-type="main" id="aab12120-abs-0001"> <title>Abstract</title> <p id="aab12120-para-0001">Perceived benefits of insecticidal transgenic crops include reduced usage of broad‐based insecticides, and therefore lower risk to non‐target organisms. Numerous studies have documented low or no direct toxicity of <italic>Bacillus thuringiensis</italic> (<italic>Bt</italic>)‐derived toxins against non‐target organisms, but there has been less research on (a) effects of secondary pest infestations on <italic>Bt</italic> expressing in crops and (b) behavioural responses by predators feeding on host arthropods from <italic>Bt</italic> crops – both topics are investigated in this study. We quantified predation by the obligate spider mite predator <italic>Phytoseiulus persimilis</italic> of carmine spider mites (<italic>Tetranychus cinnabarinus</italic>), reared on <italic>Bt</italic> or non‐<italic>Bt</italic> corn (<italic>Zea mays</italic>). Both no‐choice and two‐choice studies were conducted. In addition, we quantified toxin levels in corn leaves with/without spider mite infestation. Under no‐choice conditions, <italic>P. persimilis</italic> consumed non‐<italic>Bt</italic> spider mites at a faster rate than <italic>Bt</italic> spider mites. Under two‐choice conditions, <italic>P. persimilis</italic> spent more time in the vicinity of non‐<italic>Bt</italic> spider mites than near <italic>Bt</italic> spider mites. Corn infested with spider mites exhibited lower toxin levels than non‐infested plants. These results suggest potentially complex interactions among non‐target herbivores, their natural enemies and <italic>Bt</italic> crops.</p> </abstract>