TARGETED USE OF PESTICIDE FOR SLUG CONTROL IN COMMERCIAL FIELDS

The grey field slug (Deroceras reticulatum) is a pest of a wide range of agricultural and horticultural crops, resulting in significant economic losses in most years. For many years slug control has relied on pesticides such as metaldehyde. The use of pesticides, however, is nowadays subject to restrictions and best practice guidelines aimed at protecting water courses.

Slug population tends to form the strongly heterogeneous spatial distribution (`slug patches'). A patchy distribution of slugs where patches of high slug density are dispersed among areas of lower density may offer the significant potential for reducing use of pesticides in agricultural fields. An example of targeted use of pesticide can be found here. The example in the video shows covering with pesticide high slug density patches alone, leaving areas with lower slug numbers untreated. This is opposite to existing protocols requiring that pesticide is applied over the whole domain.

A spatial distribution of slug population in the video has been obtained from trap counts collected by applied biologists at Harper Adams University from a regular sampling grid of 10x10 sampling locations in a farm field at South Kyme, Shropshire on 18 November 2016. The model has been developed under the following assumptions:

1. A sampling grid is sufficiently fine to provide accurate information about the heterogeneous spatial slug distribution and the slug abundance in the field.

2. Subdomains with the high slug density are accurately identified and they have stable spatio-temporal distribution.

3. Pesticide application technique allows for uniform covering of the area of interest.