19 May 1995

Weevil in rape

ALTHOUGH seed weevil numbers in winter oilseed rape have risen recently, most crops remain below the spraying threshold.

Hot, dry weather prompted the rise, taking weevil populations to their peak early last week, says ADAS.

Its advice is to continue checking for the long-snouted pest. Pyrethroid sprays are recommended if two or more weevils can be found per plant.

For northern crops and crops prone to pod midge attack the threshold is one weevil per plant. An alternative approach is to use triazophos (Hostathion) at the very end of petal fall.