UA: Calcium requirements of Australian pest snails and the impact of liming

Four snail species of European-Mediterranean origin have established in southern Australia and become significant pests of grain crops: Cernuella virgata (common white snail), Theba pisana (white Italian snail), Cochlicella acuta (conical snail), and C. barbara (small pointed snail). Snails climb crop plants in spring and contaminate the grain harvest, creating significant harvest costs (harvest modifications, damage to machinery, post-harvest grain cleaning) and losses (grain value downgrades, receival rejections) for affected growers, and pose serious market access risks for the industry. Dietary calcium is recognised as an essential nutrient for snail growth, reproduction, and shell construction. Because of this understanding, affected growers are concerned about the overall impact of liming (a very accessible form of calcium) on snail population dynamics, with reports that snail numbers increase after lime application. Some growers are considering foregoing their liming program, which can have a huge detrimental impact on the farming system as without liming to counter ongoing acidification, yield continually drops. Data derived from iLime (using continuous wheat rotation for simplicity) calculated a 11% yield penalty after 10 years and a 41% penalty after 20 years. There is a significant gap in both local and international knowledge regarding the calcium requirements of the four snail species that impact Australian grains. By identifying the specific calcium needs at various life stages, understanding how calcium availability influences snail behavior, and investigating the local adaptations of these pest species in Australia, we can create targeted strategies to reduce snail damage and minimise economic losses. This investment is dedicated to understanding the impact of calcium on snail behaviour, exploring local adaptations, and developing targeted interventions to mitigate snail damage in Western and Southern Australian farming systems.