Overall risk at lowest levels since 1984
Results from this season’s Home Grown Cereals Authority‘s autumn wheat bulb fly survey suggest that the risk from this pest is relatively low; in fact, the overall risk in 2012 is equal to the lowest-level risk recorded since 1984.
A total of 30 fields were sampled, with sites split across eastern and northern England, where the pest is historically most prevalent. “It is likely that the cold and wet weather had an impact on the number of adult flies and their ability to lay eggs,” said Caroline Nicholls, Home Grown Cereals Authority research and KT manager. “However, late-drilled crops, sown after November, or slow-developing crops may still be at risk if they have only one or two tillers at the time of wheat bulb fly hatch in January/February. For these crops, a lower threshold of 100 eggs/m2 is considered more appropriate.”
In the east of England, 47 percent of the sampled sites and 27 percent of the sampled sites in northern England were above 100 eggs/m2. In these situations, late-sown crops would benefit from an insecticide seed treatment, according to the researchers.