Effective snail management requires careful monitoring of snail activity, weather conditions and soil moisture, together with the use of multiple control options.
These were among the key messages delivered by research scientist Michael Nash at a recent series of snail and slug management workshops in the Wimmera and southern Mallee attended by 140 growers and service providers.
Dr Nash explained that soil management practices that help conserve moisture can also lead to increased snail populations.
“If you’re a good farmer, you’re going to have snails,” he said.
“The first step is knowing which species you have in your paddock. All species are different ecologically and so their management is slightly different.”
Dr Nash said cheap bran-based pellets are not sufficient to drive down snail numbers and cultural and biological controls, such as cabling or rolling, are also needed.
“You will always have a snail problem if you rely on bait alone,” he said.
“Growers also need to be aware that different baits will break down at different rates depending on moisture and temperature.”
Dr Nash recommended baiting in autumn when snails are actively feeding, but before they lay eggs. He said egg-laying could occur in March or as late as the end of May, depending on the season.
Dr Nash advised growers to monitor weather conditions, including dew and humidity, and soil moisture, before making decisions on baiting.
“Recent studies with cameras suggest that snails can mate in summer if there is ongoing humid weather and enough soil moisture, as occurs in more coastal areas. However, they will not lay eggs if there is a chance the eggs will dehydrate due to low soil moisture,” he said.
“A great rule of thumb is to squeeze snails to see if they are juicy and ready to take baits. If they are pasty and not hydrated, they are not active enough to take bait.”
Dr Nash said that in very dry years, snails can skip the egg-laying process and go into ‘hibernation’ (aestivation) until the following year.
“Adult snails are great survivors and will only lay eggs when conditions are suitable,” he said.
Dr Nash suggested growers should bait a small area to determine if snails will feed on pellets before baiting a whole paddock.
He reminded growers to carefully follow label advice and ensure that withholding periods are observed as some baiting products cannot be applied whilst stock are grazing the treated area.
The snail and slug management workshops were co-ordinated by Agriculture Victoria and delivered with support from the Grains Research and Development Corporation (GRDC), the Wimmera Catchment Management Authority and the Wonwondah Landcare Group.
For more information on Agriculture Victoria events in the Wimmera and southern Mallee, contact Heather Drendel on 5083 2222.
Source: Agriculture Victoria