Crop Biotech Update

Queensland Bt Cotton Field Under Investigation

January 16, 2009

According to a report by Farm Weekly, Queensland's Department of Primary Industries and Fisheries (DPI&F) and the Cotton CRC are investigating reports of cotton bollworm survivors in Bollgard II plants in the Emerald Irrigation Area. Some 85 bollworm larvae were collected from the Bollgard II cotton at Emerald, 31 Helicoverpa punctigera and 54 Helicoverpa armigera, but there is no evidence to suggest that either species may be differentially surviving.

Susan Maas, DPI&F and Cotton CRC cotton extension officer, said that the surviving larvae had been tested but there was no evidence of any Bt resistance. "One theory is that at the peak flowering stage, there could be a dip in expression of the plant gene conferring the toxin,” Maas explained. Up to 1.5 medium to large larvae per square meter were found in the Bollgard fields in December and all affected fields were at the mid- to late-flowering stage of crop growth.

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