Virus control, as well as cabbage stem flea beetle and turnip sawfly control, mean Bayer CropScience‘s new winter oilseed rape insecticidal seed treatment, Modesto, could give the same level of yield responses as fungicides, the firm claims.

Containing clothianidin plus beta-cyfluthrin, Modesto is an improvement on the firm’s current offering, Chinook, says Adrian Cottey of Bayer. Both products will be marketed for the foreseeable future.

“We believe Modesto will affect the crop from start to finish,” he says. “Our trials suggest it can give the same level of yield response as a fungicide programme, in the region of 0.7t/ha.”

Pests controlled include cabbage stem flea beetle, turnip sawfly and peach potato aphid (Myzus persicae), his colleague Nigel Adams says.

“It gives useful control of adult cabbage stem flea beetle, helping to prevent damage to cotyledons and seedlings,” he notes. “But with a very heavy infestation, treated crops should be monitored and sprayed with a pyrethroid, if necessary.”

It will also help reduce larval infestations of turnip sawfly, an occasional pest in south and eastern England. “It doesn’t give complete control, but will eliminate the need to spray in most circumstances.”

But Myzus persicae control is the real benefit to growers. “Myzus persicae aphids spread turnip yellows virus, which can have a devastating effect on crop yields. The aphids migrate into new oilseed rape crops in the autumn, transmitting the virus as they feed.”

While Chinook was effective against these aphids, Modesto is better, he says. “In trials, it reduced aphid numbers per plant from 3.1 to 0.2. This had a corresponding reduction in virus levels, bringing them down by 60-70%.”

Modesto will cost growers around £9-10/ha, says Mr Cottey. “Pyrethroid sprays may seem cheaper, but by the time you’ve added on the costs of application, you’re looking at £15/ha.”