New thinning agent shines in first season

A NEW fruit thinning agent that has a more flexible application window than currently-available options has passed its first season with flying colours, with growers and advisors throughout Australia more than pleased with the results.

A NEW fruit thinning agent that has a more flexible application window than currently-available options has passed its first season with flying colours, with growers and advisors throughout Australia more than pleased with the results.

Registered in August last year, Brevis ® contains the unique active ingredient, metamitron, a non-hormonal agent that inhibits photosynthesis to induce fruit thinning.

Compared with currently-available fruit thinners, Brevis can be applied across a wider growth interval (8–16 mm central fruitlet diameter), a wider temperature range (10–25°C) and as one or two applications to a maximum of 2.2 kg/ha per season.

ADAMA Australia Portfolio Manager for Plant Growth Regulators, Stuart Moncrieff, says the new product has been successfully trialled by apple growers throughout all major growing regions in Australia.

“Secondary thinning is a vital management practice to optimise fruit set, yield and quality and to minimise biennial bearing,” he says

“While apple growers have access to effective thinning technology, these options are restricted by their relatively short application window or their suitability for use in modern orchard management programs.

“Brevis has a wider application window, no impact on beneficial insect species and can be used in most commonly grown cultivars in Australia, which enables growers to vary the level of thinning according to their local climate and management.

“Likewise, it can be applied using existing spray equipment, it’s rainfast within two hours of application and it has no withholding periods so it has no impact on day-to-day orchard management.”

Trials conducted throughout Australia and overseas, supported by commercial experience of the past season, have shown Brevis delivers similar or better levels of fruit thinning as currently-available options.

“Our field and technical staff worked with advisors and growers throughout the season to make sure they achieved optimum thinning results,” Stuart says.

“Last season proved to be one of those ‘hard-to-thin’ years, but most growers reported pleasing results.

“We will be sharing these learnings at grower meetings throughout the coming months, including at the APAL Industry Forum and Hort Connections Conference in Melbourne in June.”

Sam Boyce, Operations Manager for MJ Hall and Sons in the Goulburn Valley, describes how last year was a very hard season for chemical thinning on apples.

“After using Brevis last year along with some great support from the guys at ADAMA, I feel I’ll be incorporating it into my thinning programs in a big way in the future as a tool to maximise my thinning results,” says Sam.

“The benefits of this product are its capability to drop a larger amount of fruit than chemicals I’ve previously used. This is highly beneficial for me as I can reach my yield and size targets earlier in the season before hand thinning needs to occur.

“This year I hope to use Brevis on more Pink Lady and Gala varieties to further my knowledge and tailor it to fit my needs. I’m always looking to eliminate as much hand thinning cost as possible. I’m confident Brevis will really help me achieve those results as we saw a significant decrease in the amount of money spent on hand thinning last season.”

Brevis trials in Nashdale, NSW looking at BreviSmart and development work with Brevis in 2018.

Applied as a foliar spray, metamitron is absorbed primarily by leaves but does not translocate throughout the tree.

The rate of photosynthesis starts to decline within one hour of application and reaches its lowest point within three to five days of application.

Excess fruitlets stop growing and discolouration can be observed five days after application, causing them to drop for several weeks after application.

Depending on application rate, timing and environmental conditions, the rate of photosynthesis returns to normal levels within two to three weeks.

The thinning effect provided by Brevis is dependent on radiation.

There will be a stronger thinning effect if cloudy conditions exist after application, in crops under netting or if night-time temperatures exceed 10 to 12°C before or after application.

Brevis can be safely used in Granny Smith, Rubens, Red Delicious, Royal Gala, Pink Lady, Fuji and Envy apples.

“The efficacy and crop safety of Brevis in other cultivars has been thoroughly evaluated overseas – but contact your local ADAMA Australia representative for advice before using Brevis on cultivars not listed on the label,” Stuart says.

Brevis was developed by ADAMA, one of the world’s leading crop protection companies.

“The fruit thinning properties of metamitron were first identified by researchers at the well-known Fruit Research Station in Jork, Germany,” Stuart says.

“ADAMA then developed a formulation specifically for pome fruit thinning and continued development in collaboration with leading research institutes, advisors and growers throughout the world.

ADAMA is now focussed on the local roll-out of BreviSmart®, a web-based decision-making tool that utilises local weather observations and forecasts to provide ‘real time’ recommendations for the best application window.

“BreviSmart has been in global development since 2013 and we are confident of providing this service to support Australian growers and their advisors within the next season or two,” Stuart says.

“The best use of Brevis will always rely on the local knowledge of growers and their advisors, but this tool will provide added confidence in determining the optimum window for application.”