Interfarm UK’s thinning agent in apples got UK’s full approval

Just in time for the season, MaxCel® has been given Full Approval by the UK’s Chemical Regulation Directorate (CRD) for use by apple growers as a thinning agent for crops soon after flowering in order to increase fruit sizing and also to reduce alternate bearing. MaxCel is developed and manufactured by Valent BioScience, part of Sumitomo Chemical Company.

This approval will be welcomed, as it means that apple growers won’t be totally reliant on hand thinning and can benefit from getting the right balance of crop load and fruit size, explains Dr. David Stormonth of Interfarm UK Ltd.

Dr. Stormonth explains that the active ingredient in MaxCel, 6-benzyladenine, is a cytokinin-type plant growth regulator found in nature. “This group of plant hormones affects a number of processes in plants including apical dominance, axillary bud growth, cell division and growth and also leaf senescence. MaxCel prevents fruitlets below a certain size from developing further, whilst fruitlets above a certain size will successfully grow on. Consequently expensive hand thinning costs are reduced. Fruit size is also increased due to reduced competition for nutrients and due to an enhanced rate of cell division and growth resulting in increased marketable yields. Enhancement of return bloom the following year helps reduce any trend by the orchard towards alternate bearing.”

MaxCel should be applied when the king fruitlet has a diameter of 7-15 mm, with the optimum range being 10-12 mm in size. It should be applied at the start of a warming period when and the maximum daily temperatures for the 2-3 days following application are expected to be at least 15-18° C. Maxcel should not be applied when temperatures are below 15° C. One application can be made per year and the latest time of application is when the king fruitlet is 15mm.

MaxCel is recommended on all varieties of apples at dose rates of 3.75 to 7.5 litres/ha. The dose rate varies according to how easy or hard the variety is to thin and also the state of the crop. It is formulated as a soluble concentrate, ready for the grower to use and is unique in requiring no additional adjuvants. It is important to ensure adequate coverage of fruit and foliage without excessive run-off, with water volumes being adjusted according to tree size and spacing. Water volumes of 1000 litres/ha in air assisted sprayers will give adequate coverage of fruitlets and foliage. It is also important to use a water volume that allows MaxCel to be applied with adequate coverage, whilst delivering the correct amount of product depending on the variety and its ease of thinning. It is fully compatible with IPM programmes and is available in 5 litre containers.

"Achieving premium size grading is important for marketing quality produce and enhancing fruit size alone can more than pay for the treatment. The use of MaxCel can increase growers’ returns by reducing hand-thinning in apples, improving fruit size and quality. It also promotes strong return blooms for the following year, so it is not just the one benefit of fruit thinning,” says David Stormonth.