10 September 1999

Warning of flea beetle risks

ABSENCE of flea beetle control from banned Lindane (gamma-HCH) seed dressing could make a pyrethroid insecticide spray more important in oilseed rape.

An average of five cabbage stem flea beetle larvae in young plants is enough to cut yield by 0.5t/ha (0.4t/acre), warns Cyanamids David Marris.

"But the decision to act needs to be made early. Later treatment of larger plants will not give a satisfactory economic response."