Growers are reminded to avoid short gaps between spraying off and drilling, which can leave a green bridge for aphids to survive and spread barley yellow dwarf virus into new crops.
Cereal volunteers and some weed species can host grain aphids and bird cherry-oat aphids – both of which are vectors of BYDV. But infection rates are lower when there is a nine-day gap compared to just two days, according to Bayer trials.
“When there is a short interval between spray off and drilling these aphids can survive on the dying volunteers and weeds, then quickly infect the new crop as it emerges,” explains Bayer’s Matt Siggs.
The Bayer trials team set out to find the optimal interval between green bridge destruction and drilling. Infected bird cherry-oat aphids were released into plots of cereal volunteers. Plots were then sprayed off, with winter barley drilled after a two-day or nine-day gap.
Barley yields were significantly higher in plots treated with glyphosate nine days before sowing. But aphid survival was much higher in plots where there was a two-day gap – leading to significantly higher levels of infection in the crop.
Clear results
“The results are clear, try not to have a very tight turnaround between spray off and drilling where BYDV is a problem. With a short gap, aphids can survive on dying volunteers and weeds to migrate to the newly emerged crop.”
Farmers should take care to apply glyphosate at the correct rate, adds Mr Siggs. Rates might need to be higher than usual this autumn because growing conditions were good before, during and after harvest.
“We are seeing some fairly vigorous and large weeds and volunteers which will require more robust rates than may be assumed, so get agronomic advice.”
Mr Siggs emphasises that an integrated pest management approach is essential for BYDV management, utilising tools such as T-sum and selecting resistant varieties. Delayed drilling is also effective and fits in well with weed control programmes.
“Because of the longer gap between application and drilling, there could be concern about additional weed germination,” he says.
“Monitor carefully before drilling and consider Roundup in the pre-emergence mix at 540gms/ha if there is further weed emergence. But keep strictly to the true pre-emergence timing – and of course get advice about it.”
Farm suppliers appoint head of sustainability
The Agricultural Industries Confederation has appointed Vicky Robinson as its first head of sustainability for the organisation which represents the UK’s agri-supply industry.
Ms Robinson, who lead the trade association’s sustainability policy work, was previously technical director at Linking Environment And Farming (LEAF). Before that, she worked for Natural England on agri-environment delivery and policy development.
She said: “With the increasing emphasis on sustainability within our food system, the pivotal role that the agricultural supply chain provides in balancing the provision of nutritious food with the needs of the environment, economic and social systems is key.
“Working across all of the sectors that AIC represents, my role will balance the needs of our members in delivering the AIC’s mission – supporting modern sustainable commercial agriculture in the UK and collaboration throughout the food chain.”
The AIC developed its first agri-supply roadmap for a sustainable food chain in 2020. Ms Robinson will support AIC member businesses as they transition towards net zero.
