August 3, 2021 4:22 pm Published by Donna

Ensuring adequate levels of an often-overlooked micronutrient can provide apple growers with the opportunity to score on the three sought-after characteristics of color, sugar content and crispness — and an early harvest.

Molybdenum. It’s one of those awkward elements. Not only is it a bit of a mouthful to pronounce, but unlike phosphorus, potassium, copper, zinc, nitrogen and other recognizable nutrients, it’s not one that enjoyed much discussion or experimentation in science class either.

Yet despite playing a crucial and multifaceted role in plant metabolism — its most high-profile role is in nitrogen processing and fixation — Mo deficiencies are not only transient and short-lived, but virtually impossible to detect: quite different from copper or sulfur deficiencies, for example, where the leaves tell the whole story.

Mo is also essential for production of abscisic acid (ABA). “This is one of two plant hormones associated with maturity,” explains Dr. Anna Weston, of Levity Crop Science, who has been researching the important role of molybdenum in crops.

“The other ‘maturity’ hormone is ethylene, which apple growers will already know as the ‘fruit-ripening hormone’.”

But Dr. Weston says there’s a basic problem with ethylene: while it’s a ripening agent, its effect is to weaken and soften cell walls in the fruit by removing calcium.

“Ethylene is somewhat over-rated,” she says, “and using it can be a trade-off. Yes, it can lift brix and color, but by increasing softness fruits become more susceptible to blemishes and conditions such as bitter pit, reducing post-harvest shelf life.”

This is where ABA comes in. It has a similar effect to ethylene in encouraging ripeness and sugar production, but without the softness.

If it’s that simple, then why doesn’t the tree just turn out more ABA? It comes back to molybdenum — it’s often not available, or not sufficiently available, just when it’s needed most.

“Molybdenum is ABA’s limiting factor; it’s the building block in the plant’s ABA production.”

Dr. Weston’s research was how to encourage the plant to use applied molybdenum to generate ABA quickly. For this, Levity turned to one of its own ‘building block’ components, its proprietary technology. Already used in several advanced nutrition products from Levity, it ‘turbocharges’ the plant’s metabolism.

“The plant responds to Levity technology by making use of what it finds in abundance,” Dr. Weston points out, “making it invaluable as a formulation tool.“We can force the plant to use Mo more quickly, producing high levels of ABA. We’re giving the plant the resource to do what it needs to do.”

Alongside Mo with Levity’s technology, this product also includes specific cell wall protectants. These counter ethylene, enhancing the ABA effect and preventing softening of the fruit. The further inclusion of boron doubles down on sugar production.

Under the name Cell Power® Sulis™, Levity’s molybdenum product has already seen action in the U.S. market, as Dean Konieczka, consultant agronomist with OMEX® Agrifluids USA, explains.

“We started running trials with Sulis™ in 2016 to discover how Levity’s claims of earlier ripening, improved color and higher brix held up. We had already been impressed by the trial results from Britain, where Levity developed the technology and OMEX® has replicated those trials here in the United States.

“There, growers were being rewarded with significant increases in red coloration — up 15 per cent — and a big decrease in green apples, from nearly 25 per cent in the control group to just 2.5 per cent in the OMEX® Sulis™ treated block.

“While the earlier harvest permitted by a Sulis™ treatment saw no fruit remaining on-tree after second pick, untreated blocks needed a third pick and a juice pick.”

In laboratory tests the treated apples had better overall color, higher sugar content, lower starch score and higher overall sweetness. In blind taste tests, lab staff selected treated apples over the control group.

“In our own Pacific Northwest trials, and East Coast trials we saw similar results across the board,” Dean notes, “but we also looked at how Sulis™ affected bitter pit and green spot.

“In a hail-damaged crop of Cosmic Crisp, Sulis™ reduced green spot to 16 per cent, compared with untreated at 19 per cent. In Honeycrisp, Sulis™ reduced pre-harvest bitter pit to zero and kept post-harvest incidence at just 2 per cent against 30 per cent for other treatments in the trial.”

To stimulate color and brix ahead of harvest, apply Cell Power® Sulis™ as soon as fruit starts maturation, repeating the application at 7-10 day intervals.

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The product names and brands referenced here are registered and trademarks of OMEX® Agrifluids, Inc.© OMEX® Agrifluids, Inc. 2021.

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