Entomologia Experimentalis et Applicata (2007) 122, 45-51

J. van den Berg and A. Van Wyk (2007)
The effect of Bt maize on Sesamia calamistis in South Africa
Entomologia Experimentalis et Applicata 122 (1), 45-51
Abstract: Bt maize, Zea mays L. (Poaceae) expressing Cry 1Ab insecticidal proteins was introduced for control of Busseola fusca (Fuller) (Lepidoptera: Noctuidae) and Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) in South Africa after its development for control of crambid borers in North America. In the light of the reportedly lower toxicity of Bt maize to certain Noctuidae borers, the effect of Bt maize was evaluated on Sesamia calamistis (Hampson) (Lepidoptera: Noctuidae). The characteristic larval behaviour of S. calamistis may result in reduced exposure to Bt toxin and subsequent high levels of survival. Larvae do not feed on plant whorls like other borer species but penetrate stems directly from behind leaf sheaths where eggs are laid. Greenhouse and laboratory bioassays were done with three Bt maize hybrids and their iso-hybrids. 'Whole plant methods' were used and potted plants artificially infested with eggs or larvae and survival recorded over time. Larval survival was also determined on different plant parts (whorls, stems, tillers, and ears) over time. Bt maize was shown to be highly toxic to S. calamistis. No larvae survived longer than 12-18 days on Bt maize plants in any of the experiments. Adults did not differentiate between Bt and non-Bt plants in oviposition choice experiments. Sesamia calamistis is polyphagous and occurs in mixed populations with other borer species with which it shares many parasitoid species in Africa. The ecological impact of local extinction of S. calamistis caused by this highly effective transgenic event is therefore not expected to be great.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Johnnie van den Berg

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Sesamia calamistis	Maize/corn (Zea mays)	South Africa
Bacillus thuringiensis genes in crops (entomopathogen)	Sesamia calamistis	Maize/corn (Zea mays)	South Africa
Bacillus thuringiensis Cry1A-toxin (entomopathogen)	Sesamia calamistis	Maize/corn (Zea mays)	South Africa