sustainability through science & innovation

Snails

Grower, Chris Brain, has reported seeing high numbers of snails in several paddocks southwest of Ararat, in the Western district of Victoria. The species has not been confirmed however they are either common white snails (Cernuella virgata) or white Italian snails (Theba pisana). Chris says the distribution of snails is quite patchy, but in some areas densities of up to 20-30 per m² can be found. Although both of these species can cause direct feeding damage to emerging cereals, canola and pulse crops, the main issue is typically as grain contaminants at harvest.

Over summer, snails aestivate and may move up stubble, fence-posts or vegetation to rest above ground to avoid water loss. They typically become active in late summer or early autumn and remain active throughout the season until late spring. Summer rainfall can stimulate snails to become active earlier however they do not normally breed during summer.

There are several management options available to control snails at this time of year. Paddocks should be monitored for snails using small 0.1 m² quadrates (repeated randomly 10 times). If baiting is required, this should be done shortly after snails become active in autumn, and before they have begun to lay eggs. Targeted baiting can be used in areas where high numbers of snails remain (e.g. fencelines and paddock borders). As with slugs, the availability of alternative food sources and shelter will affect the efficacy of baiting. Baits should be applied when there is sufficient moisture for snails to remain active for 2-3 days following application. Threshold guidelines for white Italian and common white snails in cereals are 20 per m², and 5 per m² for pulses and canola.

Burning remains the most effective method of pre-breeding snail control. Research has found that an even burn is important for good snail control. Where snail populations are large a strategic burn, perhaps only once every three or four years, will dramatically increase the success of managing snail numbers with baits. For a comprehensive guide to snail management refer to the publication Integrated snail management in crops and pastures.

PestFacts is supported by