Baiting timing for snails and slugs

Grain industry research has found that the timing of bait applications is critical to reduce snail numbers and protect emerging crops from slugs. Understanding when individuals of different species are active, mating and breeding, underpins the successful management of snails and slugs.

With above average rainfall across large parts of the south-eastern cropping regions recorded throughout the 2022 crop season, many growers are anticipating higher than usual numbers of slugs and snails this season.

SNAILS

Wet autumn and winter conditions favour snail breeding. As a result, snail numbers increased in 2021. An AgNova project monitoring snail reproduction in South Australian vineyards to improve bait timing, observed garden snails mating over summer. Initial findings suggest garden snails are opportunistic breeders, therefore multiple applications of baits within a season will be required. The idea that snails hibernate over summer (aestivate) is misleading; timelapse footage shows snails moving whenever moisture is available and feeding once individuals are hydrated. In trials, IRONMAX Pro® was applied to a paddock in the southern Yorke Peninsula after 40 mm of rain in January. Over 90 per cent of the Italian snails feeding on it were killed. In comparison, conical snails in the same paddock did not feed on the baits – they were not in an active state.

Growers need to monitor snail activity and apply bait accordingly. In 2022, this may mean baiting from late February onwards, when round snails will be actively feeding, and again later in April, when conical snails will be actively feeding after mating. With the introduction of the iron phosphate product, IRONMAX Pro and timely follow-up baiting prior to harvest, it is possible to eliminate snails due to the nil withholding period. This newly registered product has a great fit in intensive pasture systems.

SLUGS

Slug activity and breeding has benefited from La Niña, with large numbers expected to carry over into 2022. Taking longer to grow than grey field slugs, black keeled slug numbers are expected to be greater again in 2022. In 2021, black keeled slugs were observed in April, but a large number also emerged mid-May, when the “black wave of doom” is usually observed. This is consistent with overseas research: slugs emerge from the ground over an extended period, up to nine months for grey field slug populations. What is observed on the soil surface is only the active proportion of the slug population at any one point in time; the total number is often much greater. This highlights the need to not be complacent: use long lasting baits for sustained control where monitoring of establishing crops every three to four days is not possible. In areas that had a long cool spring in 2021, numbers of grey field slugs built up as suggested by spring monitoring (see graph below). Proactive growers applied bait after seeding to protect seed and seedlings, but where branbased pellets were used, had to reapply after substantial rainfall. Those using an all-weather product, such as Metarex Inov®, were controlling slugs with this single application after 50 to 80 mm of rain.

Long term monitoring is vital to understand when snails and slugs are ready to take baits, so management can be proactive to achieve the best results.

WARATAH® FENCING – PROVEN TO BE EFFECTIVE IN THE FIELD

Feral animals, when not taken care of correctly, can cause a lot of damage and stress to any farming enterprise and reduce property yields. Dean Hague runs a mixed farming enterprise near Lake Cargelligo. However, Dean and other farmers in the area knew that the problems that they were having with feral animals were increasing. Feral animals were causing extensive damage to the landscape, crops, and to livestock. The issue was becoming very costly to all farmers and something had to be done. Dean stated, “We just wanted to try and control our grazing pressure. Because our properties are backing onto national parks, we were having a lot of trouble with feral pigs, as well as kangaroos.” Dean, along with multiple farmers in the area decided enough was enough and made the decision to collectively fence out the feral animals, forming a fencing cluster around themselves. Dean stated, “We looked through every product right up to this Waratah fence.” Dean settled on a Waratah fence because “it was over such a big area and pretty remote some of it, and we didn’t want to have to go back and keep maintaining it. It was a proven product, that has been around a long time and they (Waratah) were easy to deal with.”

THE SPECIFICS OF THE CLUSTER

The fencing cluster is a fully enclosed 210km fence covering 177,000 hectares over 16 landholders. The cluster fence design included: > 15/150/15 Stocksafe-T® Longlife

Blue® with apron to stop animals from burrowing under the fence line whilst also providing enough height to deter kangaroos from jumping the fence; > Blue latch posts, which made the fence easier to erect saving labour costs and provided strong ground holding to prevent the fence line from being compromised by charging animals such as feral pigs, and > Waratah high tensile barbed wire

Longlife Blue® across the top, providing extra height to the fence to further deter animals leaping and jumping over the fence line. All wires used in the fence were coated in Waratah’s LongLife Blue coating, which means the wire will have corrosion resistance lasting nine times longer than standard galvanised wire and 1.5 times longer than heavy galvanised wire.

IMPRESSIVE RESULTS

After the cluster fenced was established the farmers saw a marked reduction in feral animals on their properties. Dean stated “We knew it was going to work. We just weren’t sure how long it was going to be before we got the benefit. But, within six months we could see that we were starting to go forward, a year after the fence went up we went from marking 70-80 per cent (pc) of lambs to 125pc of lambs, increasing income by a few hundred thousand dollars.”

Dean had some advice for anyone considering a similar project, “it’s a big cost straight up but if you break it down to $2-3 an acre on your property, you can’t really do too much for $2-3 dollars an acre, but doing this could potentially raise your income by 20-30pc!” To hear Dean’s full story, or to listen to other happy customers, visit the Waratah YouTube page: youtube.com/WaratahFencingAustralia For more information about what Waratah can do for you visit your local Elders branch or go to www.waratahfencing.com.au or contact 13 10 80.