SLUG DAMAGE AND NUMBER OF SLUGS (GASTROPODA, PULMONATA) IN WINTER-WHEAT IN FIELDS WITH SOWN WILDFLOWER STRIPS

Previous observations have shown that slugs found favourable condition s for reproduction in wildflower strips and that they caused high dama ge to oilseed rape adjacent to the strips. In the current study slug n umbers and damage were estimated in wildflower strips and at different distances from the strips into winter wheat crops, from 1994 to 1996. Slug damage was estimated using an index of defoliation and slug numb ers and activity were measured using wheat bran traps. Investigations began when winter wheat seedlings emerged and lasted for five weeks. S lug damage was never severe in any of the fields studied. In most fiel ds, slug damage was higher close to the wildflower strips than at grea ter distances from the strips. The declining slug damage with increasi ng distances from the wildflowers strips was related to the distributi on pattern of juvenile Arion lusitanicus, suggesting that this species was responsible for the higher damage near the strips. Other slug spe cies (Deroceras reticulatum, Arion fasciatus, Deroceras laeve) were mo re or less evenly distributed over the field or were almost entirely c onfined to the wild-flower strips. Results showed that winter wheat wa s not at risk from slug feeding in spite of the establishment of wildf lower strips and that therefore the application of molluscicide along the strips is unnecessary.