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Title: INITIAL EVIDENCE FOR TOXIC EFFECTS OF CONDENSED DIETARY TANNINS ON SLUGS

Author
item O Neill, Katherine
item Godwin, Harry
item Harter, Barry

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 1/3/2004
Publication Date: 1/15/2004
Citation: O Neill, K.P., Godwin, H.W., Harter, B.L. 2004. Initial evidence for toxic effects of condensed dietary tannins on slugs. Proceedings of the 2nd Symposium, Appalachian Opportunities, Medicinal and Aromatic Plants: Production, Business, and Applications. Mountain State University/USDA, ARS, Appalachian Farming Systems Research Center, pp. 26-27.

Interpretive Summary:

Technical Abstract: Infection by meningeal worm (Parelaphostrongylus tenuis) can cause serious damage to the central nervous system of susceptible animals (e.g., goats, sheep, llamas). At present, there are no vaccines for preventing infection, and the frequent application of veterinary dewormers increases the risk of developing resistant strains of parasites. However, the meningeal worm is known to complete a portion of its lifecycle in terrestrial gastropods (slugs and snails as intermediate hosts) and disruption (breaking life cycle) during this infective stage offers an additional potential for reducing rates of infection. In this study, we tested the toxic effects of a dietary tannin (quebracho) on adult slugs (Arion ater). Adult slugs showed a significantly increased mortality (or weight loss) following the ingestion of wheat seeds soaked in quebracho (>20 mg/100 ml) relative to those fed a control diet of untreated wheat or lettuce leaves. Preliminary data indicate that toxic effects in adult slugs were also found following ingestion of goat feed (5% total diet) and the resulting manure. Initial results indicate that interaction (possible binding) with soil particles may reduce this toxicity (or delay its effects) in pastures. Additional research is needed to evaluate the practicality and efficacy of dietary tannins as a gastropod control practice under field conditions. To simulate field conditions, we have successfully tested a modified soil-on-agar method (Voigt et al. 1998). After 30-days, slugs fed wheat (control group) were normal except for weight loss. Test slugs fed quebracho at dosages >20 mg/100ml (test group) were dead, very sick, or demonstrated extreme weight loss. Further testing of this method is ongoing.