9 November 2001

Flea beetle headache

CHINOOK, the oilseed rape flea beetle seed treatment, may offer better control than banned lindane. But dont imagine it offers 100% control, says one frustrated Yorks grower.

Bill Swallow from Middleton-on-the-Wolds, Driffield, drilled 5.6ha (14 acres) of winter rape treated with Chinook (imidacloprid + betacyfluthrin) earlier this autumn. But the crop was hit hard by flea beetle forcing him to over-spray with Hallmark (lambda-cyhalothrin) twice.

"I lost one-third of the crop growth and have had the extra cost of buying and applying Hallmark. Im looking to knock £12/acre off the cost of the Chinook to compensate for that," he says.

According to his agronomist, quite a few growers have had similar problems in the area, particularly where rotations include other brassicas, as Mr Swallows does with May-drilled swedes.

Existing crops nearby are the most likely reason why over-spraying has been needed, says Chinook maker Bayer. "We have said that where pest pressure is particularly high, such as from an adjacent brassica crop, growers may need to spray as well – its on the label," explains product manager Alan Wainright.

"Chinook offers better control than lindane, which only gave 60% control, but it is not 100%. Growers still need to check their crops."

An added complication has been the presence of more aggressive Phylotreta flea beetles, favoured by the mild autumn. &#42