In the fresh potato market, few things are as unwelcome as a spud that looks like it should be planted rather than eaten.
Sprouting may be a natural process, but it’s a sure turnoff to shoppers. However, it’s a rare sight in the produce aisle, thanks to some effective sprout inhibitor products.
Chloropropham, or CIPC, has been the industry standard for nearly 50 years. It’s still considered a safe and effective compound, but its future is uncertain.
The EPA classifies CIPC as a carbamate and has placed limits on the amount of residue that’s allowed on spuds marketed to U.S. consumers. In addition, some export markets have established much lower residue levels and, in some cases, zero tolerance.
Not surprisingly, the industry has seen increased interest in alternative sprout inhibitors.
Nora Olsen, a University of Idaho potato specialist, and Mary Jo Frazier, a UI research support scientist, have evaluated the use of essential oils as sprout control agents.
They’ve seen good results with clove and mint oil, both of which physically damage sprouts. They even tried sagebrush oil, although that was mostly a bust.
However, Olsen and Frazier report that none of the alternative sprout control agents work as well as CIPC.
We have yet to see a product as effective as CIPC,” Olsen said. “It’s economical. It works well under a wide range of varieties and situations.”
If growers and packers were ever denied access to CIPC, “our industry would have to quickly devise alternative programs,” she said.
As effective as CIPC is, there are good reasons to look for alternatives.
Growers who sell to organic markets or to countries that have reduced or zero tolerance for CIPC need something else. In addition, the EPA could always lower CIPC tolerance levels here in the U.S.
Some chemical companies have recently introduced new clove oil products, making use of the research conducted by Olsen and Frazier.
Pace International’s Biox- Combo combines the sprout- killing action of clove oil with the growth inhibition of CIPC. Its ready-to-use liquid formulation is applied via thermal fogging.
Biox-Combo provides superior short, mid- and long- term sprout control. Because it reduces total CIPC usage, it
represents a “greener” solution, according to the company.
Another new product called Fresh Pack 50 is available from Aceto Agricultural Chemical Corp. Applied in combination with Shield, the company’s new emulsifiable concentrate, Fresh Pack 50 not only inhibits sprouting, but cleans up any existing buds or peepers, said Nathan Oberg of Agri-Stor Co.
“We get incredible, long- term extension of dormancy,” Oberg said. “We can burn off any existing buds, peepers or sprouts that may be on those potatoes.”
Fresh Pack 50 can be applied using conventional injection systems. No special equipment is required. Because it doesn’t contain CIPC, packers can use Fresh Pack 50 on an as-needed basis.
“It’s a very cost-effective way for you to manage or eliminate these buds or peepers,” Oberg said. “You can run this only on those loads or lots that are going to give you problems.”
Consumers today expect high quality potatoes year-round in an array of different colors and shapes, Oberg said. Trouble is, most of the newer varieties don’t store as well as Russet Burbank.
“That dictates that we have to do something to control dormancy on those potatoes,” Oberg said. “The sprout inhibitor industry is evolving and becoming more complex as our potato industry has become more complex.”
One sprout inhibitor on the horizon is Amvac’s SmartBlock. Amvac hopes to have the product available for the 2012-13 storage season, but was still waiting on EPA approval at press time.
SmartBlock represents another alternative for growers and shippers who may be eyeing export markets that have
reduced or even zero tolerance for CIPC residue.
The new product is derived from a naturally occurring compound that gives mushrooms their flavor.
“The company is excited and we anticipate launching the product for the upcoming storage season,” said John Immaraju, Amvac’s director of commercial product development.
When it’s released, SmartBlock can be used to provide full season control with just two or three applications, compared with the multiple applications required of products made from clove or mint oil, said Rick Knowles, a horticulture professor at Washington State
University who conducted initial research on the new compound.
“I think it’s another tool in the toolbox,” he said. “In our trials, (SmartBlock) beat all of those alternatives.”
Still, Knowles doesn’t expect SmartBlock to replace CIPC. Researchers also caution that SmartBlock may be less forgiving than CIPC and may require more intensive management.
Meanwhile, researchers will continue working on alternatives to CIPC as well as strategies for making it more effective.
“We will continue to look at alternatives, but people need to realize that those alternatives may not work as well as CIPC,” Olsen said.
Photo: University of Idaho Extension potato specialist Nora Olsen in the storage building at the Kimberly Research and Extension Center.