A little stress for the apple trees, much less stress for you.
Grochem is an industry leader in the development of thinning chemistry in New Zealand. The company is constantly testing and developing new options for growers and listening to industry feedback.
That’s an acknowledgement of the fact that apple thinning is critical to optimising production and return. And secondary thinning is where timing, temperature, and good judgement, are especially important.
Gary Marshall, Grochem Commercial Manager, says getting it wrong adds significant cost, and potential financial loss. “It’s make or break time. If you get it right, you can save and make a whole lot of money. If not, you could compromise the size and quality of the apples and end up with issues like branch rub or russet. Leaving secondary thinning too long or misjudging can end up meaning labour-intensive, and expensive, hand thinning. That results in significant added costs, and even potential financial loss.”
Gary says secondary thinning is ideally done after flowering when fruitlets are between 10mm-12mm in diameter. “At that point, trees are under maximum stress. They’ve got green shoots coming and having a flush of root growth and only have so much energy to give. Trees compensate by getting rid of the smaller fruitlets and concentrating energy on the king fruits.
He says there’s not just this season’s crop to consider. “You need enough resting sites on the tree to provide for next year’s crop.”
Gary says, depending on temperature and region, there are several thinning products he’d recommend, each with differing advantages.
Meteor and Brevis both have as their active active ingredient metamitron, this works by inhibiting the trees’ ability to photosynthesise resulting in shedding of weaker fruitlets. “It has an effect a bit like shade cloth,” Gary explains.
Meteor will thin fruitlets 6-20mm with best results achieved when applied when king fruitlets are 10-16mm. But, if absolutely necessary, it will still be effective at 20mm. depending on variety. “Best results will be obtained when applied under good drying conditions on a warm day.”
Registered in over 30 countries, Brevis is used in 90% of the world’s apple and pear producing nations. The product is backed by over 800 trials to date in both the Northern and Southern Hemispheres.
Like Meteor, Brevis works by reducing the production of carbohydrates so that energy is directed to the king fruits. Both products are sprayed on the leaves.
Using Meteor and Brevis, the smaller fruitlets stop growing and may start to drop from the tree in 10 to 12 days after application.
Both are relatively fast acting and not especially temperature sensitive.
It’s in the Hawkes Bay’s warmer temperatures, Gary says BAPSoL™ 100 comes into its own. BAPSoL100 contains 6-Benzyladenine (BA) a plant growth regulator. It stimulates cell division with the same, ultimate effect, of stressing the tree. The tree’s energy is directed into the king fruit and smaller fruitlets are shed.
He says BAPSoL 100 is used less in cooler apple growing areas such as Nelson and Canterbury – although that can depend on the season.
BAPSoL 100, which has been in the market for two decades also has an excellent record. Fruit thinning is slightly slower than for Meteor and Brevis at 21-28 days. It also differs in that BAPSoL 100 is applied to the fruitlets themselves.
He says all three products are superior to previously used carbaryl which doesn’t fit into today’s IPM systems. All three Grochem thinners are low toxicity and gentle on bees and beneficial insects.
Approaches to thinning vary but Gary says they should always be supported by a robust plan. He says the advice of Fruitfed advisors at this time is absolutely invaluable. “It’ll pay off for you.”
To purchase Meteor, Brevis and BAPSoL 100, and for more information on managing thinning, contact your local Grochem Commercial Manager or visit Grochem.com.
™BAPSoL is a trademark of ADAMA New Zealand Limited
®Brevis is a registered trademark of ADAMA Agan Limited
®Meteor is a registered trademark of ADAMA New Limited