PGR specialist, Fine Agrochemicals has seen a year of thriving success, courtesy of its next generation five times more concentrated 6-BA formulation, Exilis 5XL for optimum thinning in apple.

Marketing director Wim Aelbrecht says Exilis 5XL stands strong alongside the well-established market leading branded products in the apples segment Perlan (typiness, russet control) and Corto (vegetative growth control).

“Fruit thinning has been practiced for many years and serves a number of purposes. Too many fruits per tree can result in small fruit size and poor quality, breakage of limbs and exhaustion of tree reserves.

“Reduced fruit clusters color easier and are more accessible for plant protection products. In some cultivars, heavy fruiting can also partially or completely inhibit flower bud initiation.”

Fruitlets need energy to grow and remain on the tree. When the demand is greater than the supply, the weakest fruitlets will drop, but when energy is abundant all fruitlets will continue growing.

This energy crisis peaks when tree reserves are depleted. On average at 10mm stage – which is why fruitlets are so responsive to thinning at that time. “We speak of a chemical thinning window,” Mr Aelbrecht said. “After this point options slowly become less, ending in hand-thinning which is very costly and time consuming.

“Within this window, the best thinning occurs when energy demand is high and energy production is low. Besides this basic rule, a whole set of variations influence the thinning result like tree vigor, weather conditions, concentration and uptake of the product used.

“No easy exercise and you do not want over-thinning. For safe thinning growers use Exilis 5XL based on 6-benzyladenine, the well-known cytokinin for optimum post-bloom thinning in apples.”

Mr Aelbrecht said Exilis 5XL’s next generation 6-BA formulation contains 100 g/L 6-benzyladenine, which is five times more concentrated than the former exilis.

“This patented formulation continues to be very safe and highly effective, providing exceptional thinning results and improving fruit-size. Exilis 5XL’s advanced formulation delivers the same performance as exilis on a gram-per-gram basis but with the bonus of reducing environmental impact with less waste package material.”

Exilis 5XL, based on a unique SC formulation, has improved solubility, is easier to pour, easier to measure, easier to ship and easier to store. This advantageous formulation creates a vast improvement in storage and handling and with a non-dangerous goods classification is safer for operators.

“Fine Agrochemicals’ next generation formulation 6-benzyladenine offers excellent thinning results, with a positive effect on fruit size which goes beyond the direct effect of fruit load regulation: thinning reduces the number of fruits in the trees, which results in more nutrients being available for the remaining fruitlets,” Mr Aelbrecht said.

“This is the direct effect of thinning. However, 6-benzyladenine also promotes cell multiplication in the fruitlets, creating the potential for more growth during fruit development stage, independently from the thinning effect.

“Exilis 5XL also plays a key role in reducing alternate bearing to obtain a more regular yearly yield and has a positive effect on return bloom.”

Exilis 5XL is a secondary thinner designed for use on apple trees already treated at or about full bloom with a primary thinner such as NAA. Exilis 5XL is applied post-bloom in apple at 180 ml/100 L when average king fruitlet size is between 7 and 12mm, effectively regulating fruit load.

Most important are favourable weather conditions during and 2–3 days after application, above18°C –25°C. 6-BA is taken up through the leaves and young fruits. Slow absorption is ideal for best effect.

Mr Aelbrecht said Exilis 5XL continues to hold a market leading position in other important apple markets worldwide like New Zealand, Italy, Germany and the United States.

Fine Agrochemicals Ltd is a UK based company and focuses on the development, manufacture, and marketing of plant growth regulators (PGRs) for fruit, flower and broadacre crops. In Australia, Fine distributes its fruit PGR portfolio in partnership with Elders.