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A little mist goes a long way

Ever have a bin where, despite your best efforts to prevent rot, all you see are spoiled potatoes when you open the hatch? Applying fungicides or sprout inhibitors as the potatoes are placed in storage are obvious solutions, but what if the problem is the application or amount of the used product? Despite growers’ expertise, the method used for applying products as the tubers are placed into storage may be the problem.

The Mafex system sprays such fine droplets that some farmers have raised concerns about the potatoes not being adequately covered with product.

In 2010, Mankar Distributing Inc. in Woodstock, Ontario, introduced the Mafex ULV Fine Spray Unit to potato growers. Designed to apply liquid pesticides and sprout inhibitors in a fine, almost invisible mist, the easy-to-use system has been widely tested in other potato-producing countries for more than 30 years. The volume applied by the system (ULV stands for Ultra Low Volume) is so low that one grower who used it in fall 2011 was concerned about coverage.

“It puts on such a low rate that the potatoes don’t look wet going into storage,” comments Ruth Ploeg, a potato producer near Alliston, Ontario. She says that once her company, Sunrise Potato Storage Ltd., began applying fungicide with the Mafex system, they were not sure that the product was actually on the potatoes because the potatoes still looked dry. This is the first year that Sunrise used the Mafex system, and they are waiting to see how the potatoes fare through the winter in storage.

“The main benefit to growers is the more uniform coverage in terms of treating the whole potato and the reduced amount of moisture being put on the potato,” explains Nick Stam of Mankar Distributing Inc., the company that introduced Mafex to Canada. “There is less waste using this system because there is no runoff due to using a higher volume of water mixed with the product. Growers can safely use the label recommendations for their product of choice and still get good coverage without the added moisture that is common with other systems.”

“There is a lot less waste using this system, which offsets the initial set-up cost because product will be going on the potatoes and not running off,” explains Nick Stam of Mankar Distributing Inc.

Neil Kitchen, a grower near Delhi, Ontario, uses the Mafex system to apply sprout inhibitor on his tablestock potatoes going into storage and during packaging. Kitchen says very little sprout inhibitor is needed and spreading 900 millilitres of product across 2,200 pounds of potatoes in a short time can be challenging. “It’s a versatile little machine,” he says. “It is portable and adjustable and we can regulate how much product is going on. It provides such a fine mist that the potatoes don’t get wet.”

The Mafex operates on a system of centrifugal force using a rotation disc that distributes roughly 30 million droplets per millilitre of liquid. The droplets are deposited uniformly through a vertical air stream, the workings of the disc and the movement of the potatoes on the belt.

Ploeg says the unit was easy to install and was used on half the company’s crop of processing potatoes. “It just hooks up and you press two buttons to get started,” she says. “The unit also gives a warning if the spray stops to prevent an insufficient amount of product from going on the crop.”

The system includes a computer that allows the operator to control the volume of product being applied and to monitor the action of the atomizer.

The Mafex ULV Fine Spray Unit can apply liquid pesticides and sprout inhibitors in a fine, almost invisible mist.

“Moisture is such a big issue in this industry and we think we have a solution,” comments Stam. “There is a lot less waste using this system, which offsets the initial set-up cost because product will be going on the potatoes and not running off.” He says potato producers can expect to pay between $4,000 and $4,500 for an initial system.

Kitchen says he was interested in this technology and had been researching it. He is happy it is now available in Canada, and it turns out it is “perfect” for his small operation. “We need smaller, regulated amounts of product, and this works for us,” he explains.

Growers storing potatoes over the winter, who worry about sprouting and rot, will find the Mafex gives them more confidence the crop will survive the long months of storage. By storing drier potatoes, risk is reduced along with the normal problems of storage.

In this case, a little mist goes a long way to protect a valuable crop.