Time to intensify snail control measures
An intensified on-farm approach to pest snail control is being recommended as the problem continues to escalate in parts of the southern cropping region.
Unusually moist and cool summer-autumn conditions over the past couple of years have resulted in a sharp rise in snail populations and activity, leading to significant crop damage.
Grains industry and entomology authorities are advising growers and landowners to closely monitor paddocks on a regular basis and to bait snails or implement other control measures as soon as rain or showers trigger activity, in a bid to limit breeding and egg laying.
An industry workshop, convened by the Grains Research and Development Corporation Southern Regional Panel in response to the issue, has been told that favourable summer-autumn conditions require a more concerted snail control regime.
GRDC Southern regional Panel chair David Shannon says the cool and wet conditions have sparked more snail activity early in the year, unlike in “normal” years when snails are generally dormant throughout the summer.
“If there is sufficient food and moisture, snails will descend from their summer resting places and may breed opportunistically,” Mr Shannon said.
“It is therefore critical that baiting or other forms of control are activated as close as possible to a rainfall event. A shower of just one to two millimetres is enough to trigger snail activity.”
The workshop in Adelaide – attended by GRDC panel members and program managers, entomologists and researchers from South Australia, Victoria, New South Wales and the Australian Capital Territory, grain growers and consultants – was told that juvenile snails which survived over summer should be mature enough now to consume bait.
Dealing with juvenile snails has been a particular issue for grain growers due to the young molluscs’ inability to ingest current forms of bait.
Mr Shannon said that an integrated approach to snail control was required. In addition to baiting, other practices should include:
• Ensuring good summer weed control.
• Using cultural controls such as cabling and rolling if hot dry conditions persist.
• Burning, which is still a good control option for snails but a hot, uniform burn must be achieved. If other control options are feasible, burning should be avoided.
“Snails have certainly become a very serious issue in recent seasons, causing crop damage and yield losses, clogging machinery, contaminating harvested grain and posing a risk to grain exports,” Mr Shannon said.
“Snail activity is generally concentrated in coastal areas and those regions with calcareous or highly alkaline soils, particularly in South Australia and Victoria, and they also impact on pastures in mixed farming systems.”
Mr Shannon the GRDC and the scientific community were continuing to investigate alternative forms of snail control, including a new biological agent which has been undergoing trials.
Research is also looking at control of slugs which have been a major pest in southern cropping regions in recent seasons, particularly in relation to crop establishment.
Taking into consideration the latest information from experts on snail and slug lifecycles and seasonal behaviour, the GRDC is also updating various communication tools and resources to assist grain growers with their management strategies.
In the meantime, more information on snail and slug management is available at GRDC’s central online resource, www.grdc.com.au/arthropods-other.
Caption: Snails feed on emerging crops, clog up farm machinery and contaminate harvested grain.
Media interviews: David Shannon
GRDC Southern Regional Panel chair
Contact: Sharon Watt