WSU Extension

Washington State Impacts

Washington State University -- Impact 2008
Potato Sprout Inhibitor Nearing Commercial Release

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Washington State University scientists have discovered a new class of potato sprout inhibitors that could reduce production costs for commercial potato growers and processors and open export markets that have established a zero tolerance for residues of the most widely used sprout inhibitor. The research finding was licensed for commercial development in 2005. A product may available on the market as early as 2009.


About half of the 9.4 billion lbs. of potatoes grown in Washington each year are stored to provide a continuing supply to fresh markets and processing plants. Most varieties begin to sprout three to four months after harvest. Sprouting hastens deterioration and reduces overall quality. Chloropropham (CIPC), the most widely used sprout inhibitor has been on the market for more than 40 years. Growers and processors in the Pacific Northwest spend an estimated $7 million to $9 million annually to inhibit sprouting of stored potatoes.


Researchers at Washington State University have discovered specific classes of organic compounds which effectively control sprouting in storage. Many of the substances they have identified occur naturally in plants and are low in toxicity. In fact, they contribute to flavor and aroma of ripening fruits and vegetables. Some of the compounds are used in the flavor and fragrance industries and are registered as food additives. The WSU research group has demonstrated that these chemicals are effective as sprout inhibitors and leave little residue. In testing, one application inhibits sprouting for three to four months. Two applications have inhibited sprouting for more than a year. The researchers, who recently received a patent on their finding, are in the process of determining optimal application protocols for the major varieties of potatoes grown in the Northwest. They also are collaborating with the potato industry and academic partners to evaluate and develop the chemical for large scale use. WSU researchers are working with American Vanguard Corp. (which signed a licensing agreement with WSU in 2005) to identify and develop the most economical compound for commercialization. Research this past year has led to the filing of an additional patent to cover metabolites (i.e. breakdown products) of the original sprout inhibiting compounds, along with additional classes of compounds, that also have efficacy as sprout inhibitors. Other research has identified the probable mode of action of the compounds.


It is estimated that the sprout inhibitors being studied at Washington State University could reduce grower and processor costs of sprout inhibition by providing and effective competitor to CIPC. Alternative sprout inhibitors could open up export markets that have established a reduced (e.g. Europe) or even zero tolerance (e.g. Japan) for CIPC on imported potatoes. Washington State University signed a licensing agreement with the American Vanguard Corp. at the end of 2005 to commercialize the new class of potato sprout inhibitors developed by Knowles. Commercial release could take place as early as 2009. "This research has the potential to have major impact on the way that the potato growers in Washington and the world control sprouting," said Keith Jones, WSU director of Intellectual Property.




Hatch Act
WSU Agricultural Research Center
Washington Potato Commission


The principal counties served are Adams, Benton, Franklin, Grant, Multi-state, Walla Walla


N. Richard Knowles, Horticulturist
Washington State University
509-335-9502 (Phone)
509-335-8690 (FAX)


WSU Extension, PO Box 646248, Hulbert 411, Washington State University, Pullman WA 99164-6248, 509-335-2837, Contact Us