Home > AgNova Technologies recommends snail control in autumn to avoid yield loss in vineyards

AgNova Technologies recommends snail control in autumn to avoid yield loss in vineyards

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article image Snail problems need to be addressed after every harvest to achieve good snail control

Australian agricultural chemicals supplier, AgNova Technologies  advises growers to begin snail pest control measures right away to avoid yield loss later.

Summer snail infestations carry over into autumn but snails can easily be forgotten once harvest is over, as growers look to prepare their vines for another season. Snail problems need to be addressed after every harvest to achieve good snail control for the following year’s crop.

Many snail species shelter in vine canopies over summer to escape from the heat. Largely inactive, these snails enter dormancy (aestivation) when they can cause the most damage in vineyards, generally by contaminating the grape harvest.

Autumn rains and changing environmental conditions trigger snail movement from the vine canopy, breaking the aestivation phase, which is when snails will begin feeding, mating and laying eggs.

A snail management plan can minimise the impact of snail feeding damage in spring and contamination during harvest. Common garden snails grow up to 4.5cm wide when fully mature, feed on a wide range of plants and occur in most Australian viticultural regions. Severe infestations of the common garden snail in South African viticulture are estimated to cause up to 25% crop loss.

The white Italian snail is present in WA, SA, VIC, NSW and Tasmania and occurs in most viticultural regions. In addition to vines, these snails feed on cereals, legume based pastures as well as weeds such as horehound and turnip weed. Laying around 400 eggs per year, this pest can reach very high infestation numbers, requiring continuous monitoring and control.

Other snails found in vineyards include the common white snail, Cernuella virgata, small pointed snail, Prietocella (Cochlicella) barbara and pointed snail, Cochlicella acuta, which are serious pests of cereals and pastures across southern Australia.

Autumn is the right time for monitoring snails as any action taken for their control will decimate their numbers in spring. Most pest snail species in Australia lay eggs during autumn, winter and to a lesser extent spring, hence controlling snails in autumn will help to reduce their numbers and minimise the risk of damage and contamination.

Snails should be ideally hunted down during light rain, morning dew and during/after irrigation when they are highly active and easier to spot. The most likely places to find snails include the base of plants in a cover crop, in the vine canopy, near sprinkler heads or dripper points and in weedy areas.

Snails can also be found sheltering in leaf litter on the vineyard floor as well as on trellis and fence posts on the property.

Monitoring for snails around the edges of the vineyard is also important, as snails can migrate in from neighbouring areas.

Snail control measures can be implemented in late autumn and early winter in vineyards as the autumn break triggers movement and snails move down from the vineyard canopy. Killing snails during this period when they begin mating and egg laying will result in fewer eggs being laid, reducing the number of snails in the canopy at harvest.

Minimising weedy areas in and around the vineyard can help to prevent snail infestations and reduce breeding areas. Cultivation may also help to reduce the snail population.

Snail baits are still the most commonly used method to control snails, and should be applied when the snails are active and feeding. Additionally, the baits must be palatable and attractive to snails for baiting to be successful.

Weather resistant snail baits can outlast ordinary bran-based bait pellets. Snail baits should ideally be in small pellet sizes for accurate spreading.

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