Zebra chip disease doesn’t pose a serious threat to the Idaho potato crop, but the industry is focusing efforts on it since it has been found in scattered Idaho potato fields this season.
It’s just another pest, such as late blight or Colorado potato beetle, growers will have to learn to manage, said Erik Wenninger, assistant professor of entomology at University of Idaho Kimberly Research and Extension Center.
“Growers have been hit with one problem after another over the years, and this is just another issue that we’ll have to learn to live with,” he said.
Wenninger said he didn’t believe zebra chip in Idaho would be as serious a threat as it is in Texas, where potato psyllids — the insects that spread the disease — are present most of the growing season. As a result, the plants can be infected at a much younger age, increasing damage.
Still, Wenninger said he and fellow researchers have a lot to learn about the pest’s behavior in Idaho.
Joseph Munyaneza, Agricultural Research ServiceZebra chip disease affects the way potatoes store sugars and starches, creating discoloration when the tubers are baked. Until last year, for example, they believed potato psyllids didn’t overwinter in the Pacific Northwest, instead migrating into the region during late summer.
Whether because of last year’s mild weather or another factor, potato psyllids overwintered from 2011 to 2012, he said.
Zebra chip 101
Potato psyllids — insects about the size of green peach aphids — spread zebra chip when they feed on an infected potato plant, pick up the bacterium and then feed on a healthy one.
The zebra chip organism, known scientifically as Liberibacter solanacearum, changes the way the potato plant stores starches and sugars in tubers. It is harmless to humans or other animals.
When potatoes are cooked at high temperatures, such as during frying, the sugars caramelize, causing brown stripes.
The disease also affects plant growth and reduces overall tuber yield.
When the disease was first confirmed in Texas in 2000, many considered it a chipping problem or a Texas problem.
Since then, both the disease and the potato psyllid have spread to most potato-producing states and have been found in fresh-market, processing, chipping and seed potatoes.
Research conducted by Texas A&M University also has shown that no potato variety is resistant to the disease, although some varieties are mores susceptible than others.