Effects of transgenic maize expressing the Cry1Ab protein (event MON810) on locally adapted earthworms in a sandy loam soil in the Central Eastern Cape, South Africa

Abstract

This field study investigated effects of growing Bacillus thuringiensis (Bt) maize (MON810) on local earthworms in the Central Eastern Cape, South Africa. Two Bt maize cultivars (DKC61-25B and PAN6Q-321B) and their near-isolines (DKC61-24 and PAN6777) were grown in the 2009/2010 and 2010/2011 summer seasons. Earthworms were sampled after six, nine and eighteen weeks in 2009/2010 and after six, twelve and twenty-one weeks in the 2010/2011 season. The four maize treatments had similar earthworm counts, irrespective of sampling time, in both seasons. Sampling time had no effect in the 2009/2010 season, whereas the earthworm counts at 21 weeks after planting (WAP) were lower than the other two sampling times during the 2010/2011 season. The findings suggested that, at least in the short-term, growing Bt maize does not have negative effects on the numbers of the earthworms in the Central Eastern Cape, South Africa. Key words: Bacillus thuringiensis (Bt) maize, Cry1Ab protein, earthworm counts.