Crop Biotech Update

Effects of Bt Corn on the Reproduction of Non-target Pest Corn Leafhopper

May 21, 2010

A preliminary study was performed by Eduardo G. Virla of PROIMI-Biotecnología in Argentina and colleagues to investigate the relationship of Bt corn with cry1F protein to control the fall armyworm (Spodoptera frugiperda) and the corn leafhopper (Dalbulus maidis), a non-target pest. They aimed to study the effect of the transgenic corn on the process of laying eggs and the egg hatching rate of leafhoppers.

Male and female corn leafhoppers were released in cages that contained two potted plants - one Bt corn plant in vegetative stage, with two visible leaf collars and a non-Bt corn plant. The number of eggs and hatched nymphs were recorded. More eggs and hatched nymphs were observed on the Bt plant. Another field study was conducted to observe the abundance of the corn leafhoppers on the adult Bt plant and non-Bt plant and the same result was recorded; more leafhoppers on adult Bt plant. According to the scientists, Bt corn may have other effects such as attracting adults; leafhoppers competing with the target armyworm may have found refuge on the armyworm-resistant whorls of the Bt plant; and/or there might be a differential attack of natural enemies present in the non-Bt plots.

The abstract of this study can be viewed at http://dx.doi.org/10.1016/j.cropro.2009.12.019.