Applicable to canola, winter cereals, winter pulses, and summer crops.
|Objectives||Pre-sowing||Seedling – Vegetative||Grain fill / Podding||Harvest|
|Insects and damage||High risk:
All species of snails congregate at the base of summer weeds or in topsoil. Pointed snail species can also be found at the base or up in stubble as well as inside stubble stems.
Snails appear to build up most rapidly in canola, field peas and beans but can feed and multiply in all crops and pastures.
Snails are most active after rain and when conditions are cool and moist. Snails are dormant in late spring and summer.
A wide range of snail sizes are an indication of snails breeding in the area.
Round snails favour resting places off the ground on stubble, vegetation and fence posts. Pointed snails are found on the ground in shady places.
|Snails can be found up in the crop prior to harvest. Check for snails under weeds or shake mature crops unto tarps||Snails are predominantly a grain contaminant
At harvest, snails move up in the crop and may shelter between grains or under leaves. They can also be found in windrows.
The small pointed snail is especially hard to screen from canola grain due to similar size.
Buyers will reject grain if more than half a dead or one live snail is found in 0.5 litre of wheat or a 200 gram pulse sample.
|Monitor and record||Monitor snails regularly to establish their numbers, types and activity and success of controls. Look for snails early morning or in the evening when conditions are cooler and snails are more active. Key times to monitor:
|Natural enemies||Free living nematodes when carrying associated bacteria that causes snail death are thought to help reduce populations under certain field conditions.|
|Cultural control||Pre season:
Reduce contamination at harvest:
Trials with windrowed barley resulted in reduced round snail contamination. Early windrowing when cool produces better results.
|Thresholds||To control snails, apply a combination of treatments throughout the year. Thresholds can be unreliable due to the interaction between weather, crop growth and snail activity. For example; high snail populations in the spring do not always relate to the number of snails harvested. Their movement into the crop canopy is dictated by weather conditions prior to harvest.
Baiting before egg lay is vital.
|Thresholds to warrant harvester modifications are difficult to define. Contamination depends on snail types and size in relation to grain as well the position of snails in relation to cutting height.|
|Chemical control||Molluscidial baits containing either metaldehyde or chelated iron are IPM compatible. Apply to the bare soil surface when snails are active after autumn rain as early as March. Aim to control snails pre-season.||Mature snails larger than 7 mm in length or diameter will feed on bait but this can be less effective on juveniles
Bait rates need to be at the highest label rate to achieve a greater number of bait points. The actual number is yet to be determined; hence label rates may be revised ion the future.
|Rain at harvest can cause snails to crawl down from crops|
|Multi-pest interactions||Baits containing Methiocarb are toxic to a range of other invertebrates and beneficials|