Grains Research and Development

Date: 28.03.2013

Control snails this autumn to prevent crop damage

Author: Natalie Lee
Small conical snails on harvested canola stalks

Western Australian growers who had snails present in 2012 harvest samples or who have found the pests on soil beneath stubbles are urged to implement management practices including baiting this autumn.

Department of Agriculture and Food (DAFWA) researcher Svetlana Micic said Grains Research and Development Corporation (GRDC) supported research showed baits were the most direct method of control and that all types were equally effective, although none killed 100 per cent of snails targeted.

She told this year’s Agribusiness and Regional Crop Updates that there were increasing reports from WA growers of snails causing damage to crops and requiring control.

“Snails causing damage to WA crops are predominantly small conical snails which are suited to all soil types, and cropping areas where snails are most problematic include south coastal districts and some areas near Geraldton,” she said.

“In most years at least 5 per cent of broadacre cropped land in WA is damaged by snails and the potential loss of yield due to snail damage, if control measures are not put in place, is conservatively estimated at more than $6 million.”

Ms Micic said canola crops could incur damage if there were more than 20 snails per square metre at seeding time.

“It is essential to spread pellets when snails are active after rain and to apply the bait at recommended rates,” she said.

DAFWA researcher Svetlana Micic

DAFWA researcher Svetlana Micic recommends that growers implement management practices including baiting if snails are present in their paddocks.

“However, pellets alone may not provide sufficient control.

“Some farming practices such as stubble retention and lime application can lead to increased snail survival, so it is necessary to carry out additional management practices such as weed control and stubble management.

“Snails start moving about after good germinating rains in autumn, especially if the weather is still warm.

“Then breeding starts about two to three weeks after this rainfall, so control measures are most effective at controlling snail numbers if they are applied before egg laying starts.”

Ms Micic said baiting was the only control option once a crop had been seeded and trials had shown that sprays were ineffective in deterring snails from damaging crops.

Bait efficacy is affected by:

  • Bait count - snails find baits ‘accidentally’ as they move about, so do not skimp on application rates;
  • Stubble and green plants – the more green plant material or stubble residues present, the less effective the baits;
  • Age of snails- immature snails (small shells less than 7mm in height) are less likely to feed on baits. It is essential to control adult snails before they breed.

For more information about snail management download the DAFWA AgMemo Practical farm management to stop the spread of snails at www.agric.wa.gov.au/PC_95464.html or the GRDC Snail Management Fact Sheet at www.grdc.com.au/GRDC-FS-SnailManagement

The GRDC is conducting research on baits, with a focus on juvenile snail control, including formulation testing of alternative ingredients and biological control agents.

ENDS

AUDIO DOWNLOAD: Click here to download an audio grab for this media release.

AUDIO CAPTION: DAFWA researcher Svetlana Micic says snail numbers may be increasing on a farm if the pests were present in 2012 harvest samples or have been found on the soil beneath crop stubbles.

PHOTO CAPTION: Small conical snails on harvested canola stalks.

PHOTO CAPTION:  DAFWA researcher Svetlana Micic recommends that growers implement management practices including baiting if snails are present in their paddocks.

For interviews:

Svetlana Micic, DAFWA
(08) 9892 8591, 0427 772 051

Contact:

Natalie Lee, Cox Inall Communications
(08) 9864 2034, 0427 189 827

GRDC Project Code DAW00177

Region West