Published online: May 21, 2012 Insecticide
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PARMA, Idaho-University of Idaho and potato industry researchers are helping growers learn to identify the tiny potato psyllid in an effort to control the potentially serious zebra chip disease. Psyllids can carry the disease, which was discovered for the first time in Pacific Northwest fields last summer and has already cost growers in the region millions of dollars.
Andy Jensen, an entomologist who coordinates research for the Idaho, Oregon and Washington potato commissions, said psyllids are not new to this area but special attention is being focused on them now because of their ability to transmit zebra chip, which can be a very serious disease if not controlled.

"Before the disease came in, psyllids were a very, very minor pest (and) most people really didn't pay attention to them at all," he said. "Now that they're carrying the disease into potato fields, they're important and people need to learn to recognize them."

Jensen was on hand with UI researchers at the university's
Parma experiment station May 15 during a workshop where growers and other industry members were taught to identify the insects, which are a fraction of an inch in length.

The workshop, one of several held around the region recently, included a bitter nightshade plant that included psyllid eggs, nymphs and adults. Attendees were also able to look at adult psyllids stuck on yellow sticky traps growers use in the field.

"We're showing people what potato psyllids look like during all their different life stages and teaching them how to distinguish potato psyllids from other psyllids or insects," said UI researcher Erik Wenninger, a professor of entomology and extension specialist at the Parma station.

Potato grower Doug Gross attended the Parma workshop and said it was very helpful to see just how small the insects are.

He said the zebra chip issue is one of the biggest possible threats potato growers have faced in recent years and he's glad the industry is focusing on it.

"There was enough damage at the end of last year's crop for us to see how devastating it is," he said. "We take it damn seriously."

Before Jensen began studying the insects last year, researchers believed the psyllids wintered in the southern United States and Mexico and then seasonally migrated to this area.

But he discovered some wintering in this area.

"When I started studying it, I hoped I wouldn't find that," he said. "But I was able to find the psyllids all winter."

Jensen said one psyllid is too many and it's important for growers to be able to spot a problem before it takes off.

"It's very difficult to find them in the field, so if they find one, that's a serious issue," he said.

Seeing photographs of the insects is one thing but it's important growers learn to identify the insects through first-hand experience, he added.

"It's a very, very small insect so seeing them in person is the way to do it," he said.

SOURCE: Sean Ellis, Capital