Protecting oilseed rape from slug damage using metaldehyde, methiocarb and imidacloprid seed dressings

Slugs are serious pests of oilseed rape that readily kill very young seedlings and thus could potentially be controlled by seed dressing. The molluscicides metaldehyde and methiocarb, and the insecticides imidacloprid and beta-cyfluthrin were tested as oilseed rape (cv. Pronto) seed dressings in the laboratory. Metaldehyde and methiocarb were effective seed dressings and reduced slug damage, whereas the insecticides were not. When the two molluscicides were tested in a semi-field experiment, only the methiocarb seed dressing significantly reduced slug damage. In addition, slug damage was recorded in three field experiments conducted in Hampshire, Staffordshire and Warwickshire, UK during 2001 in which a range of insecticides was tested as seed treatments for oilseed rape. In Staffordshire, slug damage was significantly reduced by imidacloprid+beta-cyfluthrin and methiocarb seed treatments relative to the control. No significant effects on slug damage were observed in the remaining two field.