The influence of commercial food grade essences on the efficacy of metaldehyde for the control of Achatina (Lissachatina) fulica (Bowdich)

Abstract

The highly invasive giant African snail (GAS) has been found in several agricultural areas of Trinidad. Because this snail is able to feed on many different types of crops, it is proving to be a serious threat to the economic viability of farmers in this country. The results presented in this study are the most recent of several pest control strategies attempted. Five cotton pads, soaked with 1:1 mixtures (by volume) of each of five food grade essences (Aniseed, Banana, Coconut, Lemon and Vanilla) and metaldehyde, and a sixth pad of only metaldehyde (the control), were placed at strategic distances from each other in each of five blocked patterns at various sites in each of two locations, known to be infested with GAS. The number of snail deaths was recorded for each pad and the maturity stages of snails were noted. Summary statistics, stacked horizontal bar graphs, GLM models of the total number of snail deaths and of the deaths for each maturity stage all point to the same trends. The Banana: metaldehyde preparation was the most significantly effective in killing snails of all maturities at both locations. The immature snails were much more attracted to the essences than either the neonates or the adults. Some essences were more effective at one location and others were more effective at the other location, possibly because of odours from the crops at the two locations interacting with those of the essences and either enhancing or muting the attraction of the latter.

Keywords

• giant african snail
• food essence
• metaldehyde mixtures
• glm models