Slugs and snails are known to prefer the taste of certain plants over others. Their taste preference appears to be overruled by their dislike of particular scents.
A team of British scientists let snails eat several varieties of oilseed rape, a plant related to canola and mustard with a strong flavour and smell. The researchers determined the relative degree of snail acceptance of each cultivar and then compared that to the levels of two natural defence compounds in the plant tissues. The snails did not base their preference on the glucosinolate concentrations, which affects the flavour, but instead avoided the cultivars with high concentrations of volatile organic compounds, which give the plants their distinctive smell.
The research may lead to a breakthrough in the control of slugs and snails. Plants can be selected for high VOC content or perhaps extracts of high VOC plants can be used to discourage mollusc attacks.
Source: Something in the air? The impact of volatiles on mollusc attack of oilseed rape seedlings. Roger W. R. Shannon, Anne-Emmanuelle Félix, Guy M. Poppy, Philip L. Newland, Nicole M. van Dam and Mick E. Hanley. Annals of Botany. Volume 117. Number 6. Pages: 1073-1082. 2016
- Janet Wallace