Bt maize and integrated pest management ‐ a European perspective

Abstract

The European corn borer (Ostrinia nubilalis), the Mediterranean corn borer (Sesamia nonagrioides) and the western corn rootworm (Diabrotica virgifera virgifera) are the main arthropod pests in European maize production. Practised pest control includes chemical control, biological control and cultural control such as ploughing and crop rotation. A pest control option that is available since 1996 is maize varieties that are genetically engineered (GE) to produce insecticidal compounds. GE maize varieties available today express one or several genes from Bacillus thuringiensis (Bt) that target corn borers or corn rootworms. Incentives to growing Bt maize are simplified farm operations, high pest control efficiency, improved grain quality and ecological benefits. Limitations include the risk of resistance evolution in target pest populations, risk of secondary pest outbreaks and increased administration to comply with licence agreements. Growers willing to plant Bt maize in the European Union (EU) often face the problem that authorisation is denied. Only one Bt maize transformation event (MON810) is currently authorised for commercial cultivation, and some national authorities have banned cultivation. Spain is the only EU member state where Bt maize adoption levels are currently delivering farm income gains near full potential levels. In an integrated pest management (IPM) context, Bt maize can be regarded as a preventive (host plant resistance) or a responsive pest control measure. In any case, Bt maize is a highly specific tool that efficiently controls the main pests and allows combination with other preventive or responsive measures to solve other agricultural problems including those with secondary pests.

Efficacy of Bt maize against European corn borer in Central Europe

“…Political efforts are made in the EU to reduce the pesticide use and to increase the implementation of integrated pest management. Bt maize is one of the tools in the integrated pest management, a highly specific and highly efficient pest control measure that allows the growers to produce high-quality grain (Meissle 2011). The discrepancy between the effort to reduce pesticides used and the restriction of growing GMO based on scientifically unfounded fears of society is evident in the contemporary Europe.…”

“…Bt maize is one of the tools in the integrated pest management (IPM). Bt maize is a highly specific and highly efficient pest control measure that allows the growers to produce high-quality grain with reduced insecticide application and farm operations (Meissle et al 2011). Bt maize hybrid MON 810 is genetically engineered to express Cry1Ab gene that naturally occurs in the soil bacterium Bacillus thuringiensis (Bt).…”

Genetically modified crops in Switzerland: implications for agrosystem sustainability evidenced by multi-criteria model

“…This includes also labelling standards and thresholds definition (Aerni et al 2011;Bonfadelli et al 2007) Impact on health Potential impact of the GM on food quality and indirectly on health (f. ex. mycotoxin reduction, Meissle et al 2011) Public acceptance Consumer opinion on GM food. Based on polls and opinion studies (Aerni et al 2011;FOA 2015) …”

“…Seven pairwise comparisons from four species were made: three scenarios for comparing Bt vs. conventional maize, two scenarios comparing HT vs. conventional (Meissle et al 2011). In scenario C, wasps were replaced by insecticide spraying like spinosines or carbamates (authorised only under a derogatory regime against O. nubilalis in Switzerland).…”

“…One can argue that the alternative use of synthetic insecticides like indoxacarb (scenario C), known to be toxic at least for bees, birds, reptiles and fishes (Sanchez-Bayo and Hyne 2011), speaks for a decrease in pressure towards biodiversity in Bt compared to conventional systems. Nonetheless in Switzerland, use of synthetic insecticides against corn borers is rare (Albisser Vögeli et al 2011) making deployment of Bt maize unlikely to be a reasonable option for farmers (Meissle et al 2011). Noteworthy, secondary pests may also appear, like the western bean cutworm Striacosta albicosta, that are not affected by Cry1Ab (Zhao et al 2011;Catarino et al 2015).…”