We apologise for an error in aphid report of 27th October 2014. Updated report below.
The aphid monitoring programme conducted by Rothamsted Research has confirmed the presence of grain aphids (Sitobion avenae) that carry the kdr mutation making them resistant to pyrethroid insecticides. Grain aphid and bird-cherry aphid (Rhopalosiphum padi) are the main vectors for the transmission of barley yellow dwarf virus (BYDV) in winter wheat and barley.
Pyrethroid insecticides, such as cypermethrin, have been invaluable in the control of aphid species as they have been cost-effective. However the over-reliance of pyrethroid insecticides has resulted in resistance.
Independent trials conducted in autumn 2012 and reported at Crop Protection Northern Britain 2014 (*Dewar et al., 2014) demonstrated that Dursban® WG was the most consistent insecticide treatment when applied against resistant or susceptible grain aphid. Dursban WG achieved faster aphid control than cypermethrin, vital when combating virus transmission.
Monitor crops and where aphid species are present and pyrethroid resistance is implicated, consider an application of Dursban WG or Equity®. Trial results have shown that applications of Dursban WG applied via LERAP 3* nozzles did not reduce aphid control.
If treatment is justified use Equity at 1.0 L/ha applied in 200 to 1000 litres of water/ha.
If using Dursban WG the recommended rate is 0/6 Kg/ha applied in 200 to 1000 litres of water/ha.
An interval of 14 days must be observed between applications of Dursban WG and UNITE® or Broadway® Star, regardless of weather conditions. For approved formulations of iodosulfuron-methyl-sodium and mesosulfuron-methyl leave a longer interval of 4 weeks for crop safety.
Use low drift nozzles and extend buffer zones to preserve Dursban WG and Equity use.
For conventional boom sprayer:
- Use LERAP – low drift – three star nozzles
- AND adopt a 20 metre no-spray buffer zone (1 metre for dry water bodies)
*A M Dewar, A J G Dewar, L A Haydock, S P Foster and M S Williamson. Alternative insecticides to control cereal aphids, Sitobion avenae, that are resistant to pyrethroids. Crop Protection in Northern Britain 2014, pp 136-136