Newly-sown winter cereals and grass re-seeds following grassland in the southwest and the south midlands are now at risk from Frit fly.
Dow AgroSciences' PestWatch service reports an increase in Frit fly activity over the past week at sites in Herefordshire and Devon.
Susceptible crops include winter cereals following grass, grass re-seeds and established grassland. Frit fly larvae bore into the centre shoot causing tiller loss, stunting and sometimes plant death. Infestations result in poorly-established, patchy crops that may need re-drilling.
Dow's technical services leader David Roberts advises growers to check susceptible crops in those areas with increased risk .
"The best course of action is to use risk assessment charts. If a significant risk is identified apply Dursban WG (chlorpyrifos) at 1.0 kg/ha. Populations do seem slightly lower than at this time in the past couple of years, so if an integrated pest management system is in place drop the rate to 0.45 kg/ha," says Mr Roberts.
