Limited chemical control options and high reliance on the Group 22a insecticide, indoxacarb, for control of weevils in pome and stone fruit orchards throughout South West WA, has always meant a new option was going to be enthusiastically welcomed.

A number of weevil species are pests across most Australian apple production areas, but have a higher impact in WA, Victoria, Tasmania and South Australia, causing damage to fruit and leaves, affecting marketable fruit and tree vigour.

One of the industry’s most familiar faces, Elders horticulture specialist Dave Stewart, says the reliance on a single active ingredient for control of such an important pest is a risk to the industry.

As a result, he says the industry needs another control option desperately and when Bayer released Vayego, containing the fast acting and long-lasting Group 28 insecticide, tetraniliprole, its uptake became a “no-brainer’’.

“We really value an alternative such as Vayego to support our current control options and to bring a new dimension to weevil control,’’ Mr Stewart says.

Vayego provides breakthrough selective control of various weevil, moth, beetle and fly pest species in pome and stone fruit, as well as almonds and macadamias.

Its systemic action and residual efficacy targets multiple life stages, causing rapid feeding cessation to minimise damage, while, importantly when used as directed, it is soft on many beneficial species and offers a short withholding period.

In the Glenoran region, west of Manjimup, Mr Stewart has for many years worked closely with Bec Whittaker, farm manager at the Casotti Group’s Ladycroft Orchard property, which is experiencing a stark turnaround in weevil control in apples with Vayego after running into some significant challenges.

“We were using indoxacarb previously and we were having to deal with 60 per cent of fruit having some weevil damage – from minor stalk issues to chewings on the fruit,’’ Ms Whittaker says.

“Now we are probably only getting 5 per cent damage, so it’s a massive improvement and our pack-outs have probably improved 30 per cent.’’

Ladycroft Orchard has 50ha of Pink Lady, Gala, Bravo and Granny Smith apples and going into 2024 will be one of the few apple orchards in Australia to plant the new US variety, Cosmic Crisp, putting in 17ha of this member from the honey crisp family.

While the age of its trees range from 28 years down to 12 months, the bulk of the orchard is older trees and it has started 4ha annual replantings.

Ms Whittaker says garden weevil and light brown apple moth provide the greatest pest pressure in the orchard, and it is fortunate Vayego, in addition to controlling weevils, also targeted the moths, whilst woolly aphids and mealy bugs also can create issues.

“As well as damaging the fruit crop, the weevils chew on the trees and damage the next year’s buds,’’ she says.

“If there is some damage on small fruit, we have to spend money on re-thinning and then picking is slower as well, to ensure you are not putting damaged fruit in the bin.’’

After Ms Whittakeroming aware of Vayego via Mr Stewart, Ladycroft was one of the first enterprises to use the insecticide when registered and immediately applied it across the orchard due to the weevil pressure.

“After the first spray, we saw a lot of dead weevils and we went back in three weeks later and the population was almost wiped-out,’’ Ms Whittaker says.

“It’s a slow knockdown. You may not see dead weevils for a while, but it stops the chewing and the damage straight away.’’

This year, they applied a cover spray and then only two blocks required a second application of Vayego.

“Two blocks were showing weevil pressure, so we sprayed them and we haven’t seen any more pressure,’’ Ms Whittaker says.

To help preserve the latest insecticide, Mr Stewart urges growers to undertake insect scouting before applications and Ms Whittaker agrees the days of full cover orchard spraying are over due to the potential risk of resistance it caused.

“We address every block according to insect thresholds. We have bands in the trees that we open, count the weevils and when the numbers are up to 10-15 in a block, we know we will have a problem. When numbers are high in aone block, we will also treat the block next door.’’

She says compared with applying indoxacarb, Vayego is also more user-friendly, with various beneficial insects including ladybird beetles, lacewings and Trichogramma sp., which helped to control the woolly aphids. Ladycroft also uses beneficial insects from Bugs for Bugs to predate on pests such as two-spotted mites.

Vayego is applied at the orchard using air-blast sprayers, generally with water rates of 1000 litres per hectare to ensure excellent coverage.

Ms Whittaker adds while indoxacarb was a little sticky, Vayego is easy to mix.