It has taken little time for Adama Australia’s Brevis fruit thinner to become a key secondary thinning tool for Australia’s apple growers, and now it can be used more widely, with optimal application timing advocated by the company’s clever decision support tool, BreviSmart.

Launched in 2019, Brevis contains the unique active ingredient, metamitron, a non-hormonal agent that inhibits photosynthesis to induce fruit thinning.

Adama Australia portfolio manager – herbicides and PGR’s, Rob Walker, said compared with alternative fruit thinners available, Brevis can be applied across a wider growth interval (8–16mm central fruitlet diameter) and temperature range (10–25°C).

Mr Walker said an expanded use pattern registered last year had allowed the total volume of Brevis applied per season to be increased from 2.2 kg/ha up to 4.4 kg/ha, and it could now also be used in pears.

“The rate range of 1.1–2.2 kg/ha per application has been maintained, however, should the need arise, a second application of 1.1–2.2 kg/ha is now permitted,’’ Mr Walker said.

He said the expanded use patterns were a significant development for apple and pear producers, providing greater flexibility in effectively managing their thinning requirements.

“Timing is everything when it comes to the application of fruit thinners. To achieve the target level of fruit thinning, advisors and growers have quite a few aspects to consider.

“Variables such as flowering, pollination, fruit set, cultivar and rootstock must all be taken into account, in addition to recent and imminent weather conditions.”

Adama Australia is continuing to work with growers and advisors in demonstrating the benefits of Adama’s global decision support tool BreviSmart, which utilises an algorithm developed to predict a recommended window for applying Brevis.

Andrew Newall, Adama Australia insecticides and agtech and innovation manager, said the algorithm harnesses important factors such as location, variety and fruitlet size, along with weather that can influence Brevis’ efficacy in supporting apple advisors’ decisions on when best to apply the fruit thinner.

“The model assists advisors and growers in avoiding an application of Brevis in weather conditions that may lead to under or over-thinning,” Mr Newall said.

“After advisors enter the coordinates of the block to be treated, along with a few variables agreed with the grower, the model calculates the predicted efficacy for the following days.

“Local weather data is collected from preceding day calculations and combined with the forecasted data for the recorded location. The outcome is a recommendation of the best window to apply Brevis.

“The model provides a guide for advisors, however local experience and historical knowledge of the orchard is an essential component of applying Brevis successfully,” he said.