Aphids on the wind spread virus risk

Winged Myzus are now being found on OSR crops, with risk of spreading TuYV.
Winged Myzus are now being found on OSR crops, with risk of spreading TuYV.

Aphids that are the primary transmitters of Turnip Yellows Virus (TuYV) to oilseed rape plants have been caught in traps in all key arable growing areas for the first time last week. Monitoring of pest populations at the Syngenta Innovation Centers across the UK highlighted that Myzus persicae aphids have taken wing and are on the move.

Further monitoring of brassica vegetable crops by Syngenta Field Technical Managers has identified a huge increase in these aphid populations in warmer weather last week, along with greater numbers of winged adults that now pose the greatest risk of virus spread at the most vulnerable early stages of oilseed rape growth.

Oilseed rape growers should take heed of the early warnings from aphid monitoring to visually inspect their own crops, and be ready to spray with Plenum when infestations are found, advised Simon Roberts of Syngenta.

“It is important to get the application timing as precise as possible,” he said. “The aim is to prevent foci of virus developing in the crop from the feeding activity of infected aphids, which could then spread further as the season progresses.”

Research has shown the early-season infection of oilseed rape plants has the greatest impact on plant health, yield and oil production. Plenum treatment can give up to two weeks control of aphids feeding on treated plants.

Use informaytion from aphid monitoring to effectively time Plenum applications, advises Simon Roberts.
Use informaytion from aphid monitoring to effectively time Plenum applications, advises Simon Roberts.

Trials by Dr Alan Dewar have indicated the best results may be achieved from Plenum applications in conjunction with a high-quality methylated rapeseed oil adjuvant.

Mr Roberts highlighted that with pyrethroid resistance now so prevalent among Myzus persicae aphid populations, Plenum is the only foliar insecticide option currently available with a full label approval to control all aphids and minimize the risk of virus spread.

“Aphids stop feeding almost immediately after ingesting Plenum; although they may remain alive on the plant for up to four days, they pose no further risk of virus spread,” he added.

The build up of aphid colony numbers triggers adults to produce wings and migrate.
The build up of aphid colony numbers triggers adults to produce wings and migrate.

HGCA-funded monitoring work, carried out by Rothamsted Research, has shown up to 70% of Myzus persicae (Peach-potato aphids) could be carrying the virus - which is far higher than most aphid transmitted viruses.

Without treatment, the work has calculated annual yield losses from TuYV could be over 200,000 tonnes, costing the industry approximately £50m* a year, equating to nearly 10% of the total crop value.

Results of the Syngenta Innovation Site aphid traps are published within hours of identification on the company’s website, along with latest results of the national aphid monitoring scheme in a dedicated Plenum insect pest management area.