“We are always on the search for new products which are performing well overseas, so we can trial them locally, identify their potential in local production systems and expand the options available to Australian growers,” he said.
Ben explained that fruit thinners such as Thin-It blossom desiccant are primarily used in apples, plums, prunes and some varieties of low chill peaches to reduce fruit set and encourage more uniform crops.
“These trees are biennial bearers, growing a light crop one year followed by a heavy crop in the following year,” he said.
“Typically, growers using fruit thinners are aiming to grow more uniform crops from one year to the next, so their fruit is larger and more consistent in size as well as delivering better pack-outs in line with the needs of retailers and consumers.
“However, the challenge for growers is balancing these customer needs with growing conditions that vary from one season to the next.
“As growers know, every year is different, with variable nutrient levels and stored carbohydrate levels over winter, coupled with different temperatures, sunlight and growing conditions in orchards that growers need to manage to be successful.
“This is why growers might like to think of thinning products as tools in their toolbox to help manage all the variables in their orchards from one season to the next.”
Don’t overdo it
Ben said it was critical not to overdo it with the primary thinner early in the season, removing too many flowers which can’t be replaced and ultimately compromising the crop load.
“It’s a balance between using the blossom thinner to lower the number of blossoms and give the tree a good start, but leaving enough blossoms for secondary thinning, as the season unfolds and as the crop is developing later in the season.”
Blossom thinners in the 7 Worlds Ag range include Thin-It (ammonium thiosulphate or ATS) for thinning apples, plums, prunes and some low chill peach varieties, and NAA-20 (1-naphthylacetic acid) specifically for thinning apples.
“At blossom thinning, the aim is to retain the king bloom or king flower but remove secondary flowers from any other cluster, so the tree preserves its energy reserves for fruit production,” Ben said.
“Thin-It is crucial on flowering, but NAA-20 can be used for 10 to 14 days after full bloom.”
Don’t forget the adjuvant
Ben also recommends specialty adjuvants such as Pomade™ for use with NAA-20 and BAPSol 100 and Gro-Wet™ with Thin-It.
Adding the right adjuvant with the right product will give growers the best results and reduce the risk of damaging sensitive, high value crops like apples and stone fruit.
“There are tight windows for applying thinners correctly, so it is important to use these high performing adjuvants to ensure crop safety even at the most sensitive crop growth stages,” Ben said.
“Just a few weeks later, growers should be on the alert, monitoring crop load and fruitlet size to carry out secondary thinning with the aim of fine-tuning the crop load and avoiding the need for hand thinning in the orchard.”
Secondary thinners such as BAPSol 100 (6-benzyladenine) are another tool for fine-tuning apples and pears later in the season when the fruit are 7–12 mm in size.
“Depending on the weather conditions, it can all happen quite quickly in the orchard, so four to six weeks after blossom thinning, growers may choose to apply BAPSol 100 as a secondary fruitlet thinner,” Ben said.
“Secondary thinning is another option if weather conditions prevented growers from using blossom thinners earlier in the season, so it’s another tool they can use in the correct window.”
Ben likened the performance of orchard trees to vehicles, comparing the four- cylinder engine with a V8.
“The four-cylinder engine can only go so fast, just as the fruit tree only has a certain root mass and energy capacity for converting carbohydrates into fruit,” he said.
“Fruit thinning products like Thin-It, NAA-20 and BAPSol 100 help growers to maximise the production of well sized, high-quality fruit that customers are looking for.”
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