Solving biennial bearing

November 2013 | Prepared by John Wilton, Ross Wilson and Steve Spark, AgFirst | Future Orchards® Orchard Walk notes

AgFirst identifies biennial bearing as a significant problem in Australian orchards, with local microclimates often making the swings between on- and off-crop years more extreme. Fuji, Red Delicious and Golden Delicious are highlighted as particularly prone, while Cripps Pink and Royal Gala are generally less susceptible but can still become biennial after crop failure or severe over-cropping.

Once an alternating pattern is established it is difficult to correct with one action. The notes advocate a multi-faceted approach that combines crop-load management with the other husbandry practices known to influence flower initiation and tree balance. The objective is not only to manage the current crop but also to protect next season’s flower production.

Early thinning is central to this strategy because return bloom is affected while the current crop is still developing. Vigour management, pruning, growth regulators and other techniques may also be required, particularly in blocks where the biennial pattern has become entrenched.

The resource encourages growers to treat biennial bearing as a whole-tree and multi-season management issue, using block history and crop counts to assess whether actions are actually improving regularity of production.