Following the revocation of neonicotinoid seed treatments, this autumn will be the first season in which cereals will be heavily reliant on cultural control and foliar applications to combat the spread of BYDV (Barley Yellow Dwarf Virus). Foliar pyrethroid sprays have some efficacy against the vectors of BYDV (bird cherry aphid and grain aphid), however due to 50% of the grain aphid population being resistant, control is limited. Justification of pyrethroid use is therefore reliant on thresholds being reached to help to slow the spread of resistance.
Typically, a late drilling date would see plants emerging when aphid populations were lower whilst complimenting cultural control for blackgrass. However, this shortens the window in which fields are accessible should foliar sprays need to be applied, which will be more critical this season. Monitoring the aphid migration forecast will ensure growers are more aware of when to monitor crops more closely so control can be employed at the correct timings. The southern region of England is in a particularly high-risk area.
Cultural controls include increasing seed rate, destroying the green bridge, encouraging populations of natural predators through buffer strips and beetle banks, using forecasting systems and monitoring systems such as aphid news. Breeders are working on resistant varieties; however, it will be a couple of years before they become commercially available.
Bartholomews are currently undertaking extensive trials, at their regional trial sites, testing current insecticide performance in the absence of seed dressings, as well as a potential future chemistry which should be entering the UK market soon. Come to the open days to see the results and keep up to date with best practice for the coming season.