Targeting perfect chemical thinning

September 2021 | AgFirst | Future Orchards® presentation

This AgFirst presentation frames chemical thinning as a major profitability and labour-management decision rather than a routine spray program. With weaker returns in 2021 and uncertainty around casual labour availability, the presentation argues for more disciplined thinning on low-margin blocks while protecting the blocks responsible for most orchard profit.

The material stresses that apple orchards are dynamic systems and that optimum crop load cannot be achieved through a recipe approach. Biennial status, flower strength, bud density, wood type, weather and block economics all affect the level of thinning risk a grower should take.

The chemistry toolbox includes bloom thinners such as ATS, Ethephon and NAA, fruitlet thinners such as BA, metamitron and Carbaryl, and combinations of products where appropriate. The presentation also warns against over-thinning varieties prone to biennial bearing or internal disorders, including Kanzi, Jazz™ and Envy™.

The broader message is to separate “money blocks” from lower-margin blocks, define crop-load goals before spraying, use the available chemistry strategically and plan how vigour will be managed if a block is over-thinned.