Slugs In Crops: The Back Pocket Guide

Slugs have become an important pest group attacking Australian grain crops as farming practices have changed. Slug infestations cause crop damage and yield loss from their feeding and incur significant field control costs. Expenditure on molluscicides in the Australian market continues to increase annually by more than $440,000, indicating slug and snail threats are increasing.

All species found in Australian agricultural areas are exotic, originating from Europe and America.  Of these, only a few species are considered major crop pests: black keeled slug, grey field slug and, to a lesser extent, brown field slug, which comprises two species that cannot be distinguished without dissection.

The main slug species do differ in appearance and can co-exist in the same area. Incorrect identification can lead to ineffective control as timing of controls misses peak activity or controls are applied to non-pest species. A simple key and guide are provided to assist growers in the identification of the most commonly observed slug species found in Australian cropping regions. Distribution maps for the main slug species encountered from a
GRDC survey are included.