In this section:
Snail Monitoring
Why?
Knowledge of the type of snails present (round or conical), the number of each type and the sizes present is necessary before the appropriate management decision can be made.
When?
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before and after stubble management
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before and after burning
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before and after baiting
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after seeding
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before harvest
Snail monitoring should be part of all grain growers routine checks. Counting snails 7 days after controls have been applied provides an indication of success or otherwise.
How?
Only count live snails as these can reproduce, cause crop damage and move into the mature grain. The body of a live snail is visible and withdraws into the shell when poked. During dry conditions and the summer live snails close the shell opening with a layer of mucus and calcium.
The number of snails per square metre is the recognised measurement of snails. Taking counts in representative areas across the whole paddock is important.
To sample snails, use a 0.1m2 (32cm by 32cm) quadrat. place the quadrat on the ground and count all live snails within it. If two snails groups are present (round and conicals) record the number of each group separately. To determine the size groups, place the snails found in a sieve box and shake gently to separate into two sizes - 7mm and larger and 7mm and smaller. Round snails and conical snails less then 7mm are unlikely to be controlled by bait. The length of the conical snails is best determined by measuring. Draw a 7mm line on your recoding sheet as a quick guide.
Sieve boxes are a quick way of separating different sized round snails. These can be constructed from two stackable containers eg sandwich boxes. The bottom is removed from one and replaced by punch hole screens. Suggested screen size is 7mm round or hexagonal.
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5 counts along the fence at approximately 10 metres apart.
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5 counts into the paddock every 10 metres.
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record 2 size groups, less then 7mm and greater then 7mm.
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record live snails before and 7 days after paddock operation
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calculate reduction
Sieve boxes
Autumn
| Snail activity | What you should do |
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Winter
| Snail activity | What you should do |
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Spring
| Snail activity | What you should do |
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