Efficacy of mollusk baits containing methiocarb, metaldehyde, and iron phosphate against the gray garden slug, Deroceras reticulatum (Muller) infesting globe artichokes.

摘要

The gray garden slug D. reticulatum is a serious pest of globe artichokes grown under perennial culture in California, USA. Conventionally, growers have relied on various brands of mollusk baits containing metaldehyde. In recent years, however, the slug infestations have escalated significantly in spite of making 3-5 applications of these baits during crop's early stage. A field study was undertaken in California during 2004-05 to evaluate the efficacy of various slug management strategies using baits consisting of methiocarb, metaldehyde, or iron phosphate as the active ingredient. Methiocarb (Mesurol Pro), belonging to the chemical class N-methyl carbamate, was found to be highly effective in controlling the slugs and consequently in reducing their feeding damage to the buds. One application of this bait at cut-back was as effective as up to 4-5 applications of other baits containing metaldehyde. Its application at cut-back followed by two applications of metaldehyde bait (Deadline) at the peak of slug activity in July through September assisted in keeping the bud damage to minimum. OrCal's experimental "non-pelletized" bait consisting of metaldehyde-impregnated rolled-oat flakes was also more effective in controlling the slugs and in reducing bud damage than the other conventional baits. The application of this bait resulted in significantly greater number of point sources than any other pellet bait, which must have contributed to its high efficacy. Further, the flat flakes stuck better to artichoke foliage providing superior control of foraging slugs. The efficacy of iron phosphate (Sluggo) was on par with Deadline M-P and Bullet. This bait provided an effective and environmentally safe alternative to metaldehyde particularly during crop's production phase, when the use of metaldehyde bait could result in the unwarranted contamination of artichoke buds. Of all the registered metaldehyde baits, Metarex yielded the maximum slug control, which could be attributed to its high palatability, stability, resistance to wet conditions, and smaller pellet size..