BYDVseed treatment divides views
BYDV seed treatment is now approved for use on winter wheat and oats, but opinion is divided on its use.
Active ingredient imidacloprid is combined with biternol and fuberidazole as Sibutol Secur. Manufacturer Bayer says it will be competitively priced, equivalent to the cost of two pyrethroid sprays plus the cost of application, and the big advantage is that there is no need to watch for aphids or rush out to hit them at the right time. Protection is there from drilling, it adds.
But Banks Agriculture technical director Bob Mills stresses that BYDV seed treatments are only justified where two or more autumn aphicides are sure to be used. For most growers this means first half Sept drillings.
"For those in high risk areas, seed treatment will be very cost effective, but for the majority of situations a single application of a pyrethroid offers a more cost effective solution."
At 165kg/ha (1.3cwt/acre) of seed, the barley treatment Raxil Secur (tebuconazole + triazoxide + imidacloprid) gives systemic protection from aphids for £10-11/ha. This could prove worthwhile on first half Sept drillings, or up to the end of Sept in high risk areas, he notes. But elsewhere checking crops from the two and a half leaf stage, and spraying at the first sign of aphids may be more cost effective.
Second generation pyrethroids, such as Hallmark (lambda-cyhalothrin) or Decis (deltamethrin) can help extend cover, as they provide a week or two longer persistency than cypermethrin, he adds.