PARMA, Idaho-A series of workshops to help potato growers, consultants, fertilizer and chemical dealers, and processing company representatives included a May 28 session at the University of Idaho's Parma Research and Extension Center.
Focused on helping participants identify the tiny, cicada-like potato psyllids (pronounced sill-ids), workshops were organized in May and June by the Idaho, Oregon and Washington Potato Commissions.
The first psyllid monitoring workshops in Idaho were held in 2012 in Parma, Rupert and Idaho Falls, with similar workshops held in Washington and Oregon, Jensen said.
The potato psyllid is a carrier for the bacterium Candidatus Liberibacter solanacearum, which leads to zebra chip disease. Long known as troublemakers elsewhere, potato psyllids and zebra chip were first discovered in Idaho in October 2011.
This plant disease causes dark stripes to develop in infected potato tubers that turn a darker color once sliced and fried. There are no known health or nutritional risks associated with the disease, only a bitter taste.
By late June one potato psyllid was found in one Elmore County potato field and another in Ada County. Four potato psyllids were found in Canyon County fields, and two potato psyllids were found in Twin Falls County. A single potato psyllid was found in Canyon County the previous week. This psyllid and all others collected so far are being tested for the bacterium that causes zebra chip.
Erik Wenninger, UI entomologist based at the Kimberly Research and Extension Center, and his team found one adult psyllid on a yellow sticky card sample from a site with bittersweet nightshade last March. Since then, more yellow sticky cards have been placed in areas around Twin Falls with bittersweet nightshade. These sites will be periodically monitored throughout the rest of the year and through next winter.
In early June, an adult potato psyllid and numerous psyllid eggs were observed on bittersweet nightshade in Twin Falls.
This year's sampling program reflects lessons learned in the past.
"What we found last year was that the incidence of psyllids was fairly patchy across our sites. So we realized that we really needed to sample more fields. But there are only so many people and so many dollars to throw at that," Wenninger said. "There are certainly more places where we could be monitoring during the off-season after this summer."
Results from the current monitoring program are available weekly online at http://extension.uidaho.edu/kimberly/2013/04/2013-psyllid-updates/ through the Kimberly Research and Extension Center and http://www.tvpestalert.net through the Pacific Northwest & Treasure Valley Pest Alert Network.