Evaluation of Copper Hydroxide as a Repellent and Feeding Deterrent for Cuban Brown Snail (Mollusca: Gastropoda: Pleurodontidae)

Repellents and feeding deterrents are underutilized tactics for plant pest damage suppression. Here I report on laboratory and screenhouse studies that assessed a copper hydroxide-based fungicide as a chemical barrier to prevent the Cuban brown snail, Zachrysia provisoria (Pfeiffer, 1858) (Gastropoda: Pleurodontidae) from accessing plants and from feeding on foliage. This snail species is considered to be one of the most important molluscs affecting plants in Florida. Studies were conducted as a follow-up to previous research with different molluscs that demonstrated the potential usefulness of copper hydroxide formulated in a commercial fungicide as a repellent. Although the residue of copper hydroxide displayed repellency to Z. provisoria in laboratory studies, it did not effectively prevent snails from climbing the sides of pots to access plants in screenhouses. Addition of 2 spreader-stickers, Bonide Turbo (R) and Southern Ag (R), to the copper hydroxide to enhance retention of the fungicide did not improve performance. However, when copper hydroxide was applied to pots and foliage, feeding on vegetation was significantly suppressed under screenhouse conditions. I attribute these results to better fungicide residue persistence on foliage than on plastic pots.