Crop damage caused by snails, slugs and slaters, including at seeding time, has increased in the past 10 to 15 years in Western Australian grain growing regions since the adoption of no-tillage farming practices.
Responding to this situation, the Grains Research and Development Corporation (GRDC) has released a new publication 'Mitigating snails, slugs and slaters in southern Western Australia', which provides information that can help grain growers to reduce the numbers of these pests on their farms.
GRDC grower relations manager – west, Lizzie von Perger, said the booklet, written and compiled by grower group Stirlings to Coast Farmers (SCF), combined research outcomes and the experiences of local grain growers and growers from other states including South Australia.
"The publication was initiated as a result of the Albany and Esperance port zone GRDC Regional Cropping Solutions Network (RCSN) identifying snails, slugs and slaters as a priority issue for local growers," she said.
"It outlines how a consistent approach to integrated pest management throughout the year should help to reduce numbers and damage to manageable levels and prevent them from becoming a more significant problem."
Ms von Perger said snails were the most widespread of the three pests in WA and, as well as damaging grain crops at germination, could potentially cause costly downgrades of harvested grain if they were not carefully managed.
SCF research and development coordinator Nathan Dovey said snail mitigation activities needed to occur throughout the year to reduce numbers and minimise crop damage and maintain grain quality.
"Baiting remains a key tool for all growers and generally they are baiting earlier in the season and/or after seeding but before crop emergence," he said.
"However, it is important to use other mitigation strategies, in addition to baiting, to provide adequate snail control in the long term.
"The growers interviewed for the booklet found that with no control and the right environmental conditions, snail numbers could build up quickly, so consistency and timing are important."
Mr Dovey said slug damage was steadily increasing across the medium to high-rainfall zones, with emerging canola crops being particularly vulnerable.
"Some growers, however, have found snail control practices also help to control slugs, as the two molluscs can be present in the same paddocks at the same time, and have similar life cycles and behaviour," he said.
"However, slugs may require more moisture to become active and emerge later in the growing season than snails, so baiting programs are generally required later and for longer than those required for snail control."
Mr Dovey said slaters had been in farming systems for some time but had only recently begun to damage emerging canola crops in certain conditions.
"Slater damage is so far confined to specific areas and information about their behaviour and management is limited compared with information available for snails and slugs," he said.
"Since slaters normally feed on decaying matter, it is unclear why slaters may switch to eating crops.
"The GRDC and CSIRO have invested in research to determine why slaters switch from eating decaying materials to emerging crops."
'Mitigating snails, slugs and slaters in southern Western Australia' is available on the GRDC website
