Western Victorian harvest faces snail contamination risk
Grain growers in Western Victoria are being advised of an increased risk of snails contaminating grain this harvest.
Snail contamination can result in clogging of machinery and potential downgrades of cereals, pulses and oilseeds.
Victorian entomologists warn that the build-up of extreme snail populations during the 2011 cropping season in the State’s west has increased the potential for significant issues at harvest.
PestFacts South-Eastern co-ordinator Dr Paul Umina, of cesar, says growers must monitor snail populations (particularly numbers that are similar in size to grain) prior to harvest to determine the need for header modifications.
“They should also be to be aware of receival standards for grain contaminated with snails,” said Dr Umina, whose work is supported by growers and the Australian Government through the Grains Research and Development Corporation’s (GRDC) investment in the National Invertebrate Pest Initiative (NIPI).
Dr Umina said that during spring snails increasingly move into the crop canopy in preparation for summer aestivation.
“This means that any snails in the canopy above cutting height and also in windrows are often harvested along with the grain.
“If snails are present in crop canopies or windrows at harvest time, the options available to growers to reduce snail contamination are limited.”
Dr Umina said strategies to reduce snail intake are generally more effective when applied early in the harvest season when fewer snails are present in the crop canopy, snails are more easily dislodged from plants with lower grain losses, and they still respond to moisture events by descending down the plant canopy to resume feeding.
Dr Umina said that once this year’s harvest is completed, growers in areas which experienced snail infestation should focus on agronomically-balanced strategies to reduce snail carryover into next season, such as:
• Controlling summer weeds to remove food and moist shelter sites
• Bashing stubble on hot days (over 35C) and autumn burning
• Early baiting when moisture triggers snail activity but before egg-laying commences, typically in late summer/early autumn
More information on harvest techniques and integrated snail management is contained in the GRDC publication Bash 'em, Burn 'em, Bait 'em which is available for viewing and download via www.grdc.com.au/GRDC-Snails-BashBurnBait.
The GRDC also has available a Snail Identification and Control Back Pocket Guide which helps growers identify the snails that are pests of crops and pastures and outlines year-round control strategies. It is available for viewing and download via www.grdc.com.au/GRDC-BPG-Snail.
Further information on integrated pest management is available from the GRDC via www.grdc.com.au/pestlinks.
Caption: Summer management of snails, including bashing stubble on hot days, should be a priority to reduce snail carryover into next season. Photo courtesy SA Research and Development Institute.
• More information is available from Paul Umina or Stuart McColl on (03) 9349 4723
• GRDC Project Code: CSE00046
• This media release and other media products are available via www.grdc.com.au/media
GRDC Project Code