Location: Forage Seed and Cereal ResearchTitle: COST AND BENEFIT IN CONTROL OF THE GRAY FIELD SLUG IN WESTERN OREGON Author
Submitted to: Seed Production Research at Oregon State University
Publication Type: Experiment Station
Publication Acceptance Date: 3/1/2010
Publication Date: 3/31/2010
Citation: Gavin, W.E., Hoffman, G., Banowetz, G.M. 2010. COST AND BENEFIT IN CONTROL OF THE GRAY FIELD SLUG IN WESTERN OREGON. Seed Production Research at Oregon State University.129:21-24. Interpretive Summary: The rising cost of slug control products and operating inputs, and an increased awareness of environmental concerns require an informed strategy for reducing slug damage to emerging grass seed crop seedlings. We investigated how different product types, product application rate and application cost contributed to reductions in slug populations in a controlled laboratory setting. We also evaluated the impact of these baits on slug egg fecundity and how that might affect numbers of slugs during future cycle outbreaks.Our greenhouse experiments showed that there is a diminishing improvement in slug control and seedling survivorship as the rates (cost) of applications increased. This means that with increasing cost the improvement in slug mortality declines for a given increase in dollars spent. There were differences among products. The most cost effective was Sluggo (P <0.0001), while the MetaRex, Durham 3.5 and OR-CAL were least effective. The point at which higher application rates of slug baits results in diminished increases in slug mortality and seedling survival occurred at a point when only 30-45% of the slugs have been killed, and 50% of the seedlings have survived. There were differences in the cost effectiveness of the products tested in how they affected slug mortality, seedling survival, and slug egg laying.
Technical Abstract: Greenhouse studies were conducted to quantify the impact of a selection of slug baits on slug mortality and on slug-associated damage to perennial ryegrass seedlings along with the relative costs associated with utilizing specific slug control strategies. We evaluated slug mortality, egg fucundity, and seedling damage in fourteen bait and combination treatments and compared these results to untreated control groups. There was a point at which diminishing cost effective returns occurred, and this point generally coincided with 30-40% slug mortality and 50% seedling damage. The most cost effective product was Sluggo (P <0.0001), while the MetaRex, Durham 3.5 and OR-CAL were least effective. Egg fecundity had a polynomial relationship to Cost, where diminishing returns were reached when slug control costs increased above $20-$25 per acre.