Bt corn more susceptible to aphids
Research into the environmental impact of genetically modified crops appears to be accelerating. Among several recent investigations, a Swiss study published in the journal PloS ONE has documented greater susceptibility to aphids among GM maize lines than among their conventional counterparts.
The aphid under observation was Rhopalosiphum maidis. Researchers at the University of Neuchâtel studied six lines of Bt corn containing an insecticidal gene derived from Bacillus thurigiensis. Although highly toxic to feeding caterpillars, the toxin produced by the bacterial genes does not affect the aphids.
Researchers with the university’s National Centre of Competence in Research (NCCR) Plant Survival believe that the introduction of the bacterial gene produces changes in the plant’s chemistry in addition to the production of the Bt toxin.
The economic consequences of this discovery are mixed. In some regions, the aphids are considered desirable. For example, the honeydew they produce can feed beneficial insects such as the parasitic wasp Cotesia marginiventris, which lays its eggs in caterpillars which feed on the plants. However, the aphids are considered pests in regions where they damage plants by transmitting viruses, a problem which would be amplified by the Bt corn.