Slug preferences for winter wheat cultivars and common agricultural weeds.
Slugs are a serious pest of many crops, including winter wheat, but current methods of control are unreliable. As part of a research study into the possibility that alternative food sources may reduce slug damage to winter wheat crops, the relative palatabilities to field slugs (Deroceras reticulatum) of different wheat cultivars and common agricultural weeds were examined. Individual slugs were given one of 12 winter wheat cultivars for 72 h, either as seeds, germinating seeds or young leaves. Individual slugs differed considerably in the amounts of wheat eaten, but there was no clear correlation between slug weight and amount consumed. The slugs did not exhibit any preferences for cultivars at any stage of development. When individual slugs were offered a choice of the leaves of one of 12 common weeds together with wheat leaves, they manifested a hierarchy of preferences for the weeds, some of which (Taraxacum officinale, Capsella bursa-pastoris, Trifolium repens and Chenopodium album) were preferred to the wheat leaves. There was some evidence to suggest that when slugs were exposed to less preferred weeds, they consumed less overall, but they ate more wheat than slugs given palatable weed species. The results indicate that the choice of wheat cultivar would not affect levels of slug damage. Weeds could potentially act as a readily available source of alternative food for slugs in the field as part of an integrated pest management programme for slugs. However, because weeds vary considerably in their palatability to slugs, the degree of protection afforded to a wheat crop would depend on the palatability of the weed species present.