21 July 1995

Weevil monitor spray guide

WEEVIL control in peas and beans is set for a boost from modern pheromone technology. The result could be fail-safe control without routine spraying.

Current strategies involve treatment once characteristic leaf "notching" is seen. While that controls the pest, it does not always give a yield response, Antony Biddle of the Processors and Growers Research Organisation (PGRO) told visitors to the British Edible Pulse Associations annual open day at the PGRO.

The new approach monitors pest levels before crop emergence, so applications are timed more effectively.

Special "weevil traps" containing an attractant chemical developed with Rothamsted Experimental Station are placed in the pests over-wintering sites in hedge bottoms beside last years pulse fields. The number of weevils caught indicates the risk of attack a week before damage appears in emerging crops, said Mr Biddle.

If pest numbers are high, an emergence spray ensures optimum control. If they are low a spray can be saved with confidence. The approach is being evaluated and commercial interest has been shown, he added.