BYDV threat to increase
High numbers of aphids have come in following the recent warm, dry spell of weather where crops have established well and are at the 1 true leaf stage.
The main vectors for BYDV are Grain aphid and Bird Cherry-oat aphid.
- Once aphids have the virus, they will be able to transmit for the remainder of their lives.
- Plants can be infected ~30 minutes after the aphid has started feeding.
- Aphid population increase during warm autumns and the earlier the infection, the worse the impact on yield.
Insecticide seed treatments will have activity for up to 8 weeks, a follow-up spray will then be required if populations remain high. HALLMARK ZEON is the most persistent pyrethroid available. Applying 50 mls/ha will reduce the need for several follow-up sprays and help reduce the risk of resistance build-up.
Insect traps at Rothamsted are recording high numbers of Bird Cherry-oat aphid and Grain aphid this autumn, the highest in 5 years.