Bernadette Simmonds, of Invercargill, asks :-
If a container of alcohol is left out for slugs and snails will they become intoxicated or die?
Abie Horrocks. a zoologist who is studying slugs at Crop and Food Research, responded.
In a forest environment slugs help disperse seeds and spores and break down decaying plant matter. Both important ecological processes. But in the garden and in agricultural crops they are not considered so useful as they are always eager to consume a large amount of food and are responsible for devouring a wide variety of vegetables in your garden. Farmers have particular troubles with slugs when it comes to establishing clover and pea crops.
It is because of this insatiable appetite that slugs (and snails) are drawn towards alcohol. Beer is best due to its strong scent of malt and yeast, as it is the smell that attracts the voracious creatures (a mixture of yeast, flour and water would also do the trick). Containers sunk in the ground, filled with beer, will attract the slugs who will crawl in and drown (this is called a pit fall trap). The rims, however, should not be flush with the soil otherwise beneficial beetles may also crawl in and drown. This is not desirable as certain beetles eat the slugs and so can help keep numbers down.
One of the projects that I am presently working on is looking at slug control from an integrated pest management (IPM) point of view. This involves such things as carefully monitoring all pests (including slugs) with the intention of reducing unnecessary pesticide use, utilising IPM compatible chemicals (ie ones that do not also kill beneficial insects such as carabid beetles that prey on slugs), and keeping on top of slug numbers even when crops not susceptible to slug damage are in the ground. First though we need to try and better understand the habits and life cycle of the different slug species. It is important to understand what we are dealing with so that the most efficient and cost effective control methods can be implemented.