Haanchen mealybugs have been discovered in barley fields near Conrad and Valier, but Montana State University researchers are asking growers to refrain from spraying or other treatments until they can find some answers.
No effective insecticide has yet been developed to control the pest, and other factors may actually be causing yellow leaves and poor root development of some Pondera County barley plants, says Greg Johnson, veterinary entomologist for MSU.
Some other possibilities causing the crop problems include drought, aphids, brown wheat mites, lack of fertilizer or barley yellow dwarf virus, he notes.
"Just because a farmer will see these symptoms doesn't necessarily mean it's caused by the Haanchen mealybug," Johnson warns.
MSU Extension Agent Dan Picard says farmers in the county began reporting mealybugs as early as spring this year. Teton County reported them last year and in 2007, but Ponderosa County appears to be a current "hot spot."
Losses can be substantial. One producer claims his potential yield of 100 pounds of barley an acre fell to 20 bushels on an irrigated field heavily infested with the mealybugs. The pest caused a reported $5 million in losses for Idaho growers in 2003.
Local Montana producers say they expect to see some damage, but do not feel it will approach levels seen in Idaho.
Some of the affected Pondera County farmers produce brewing barleys, while others produce feed grain. Picard says Busch Agricultural Resources, one of the brewing barley buyers, has advised growers to continue raising crops for now as if everything were normal.
Johnson and other MSU researchers continue to work to discover solutions. Cecil Tharp, pesticide education specialist for MSU, is also conducting experiments to find the most effective control product. He expects results to be published this fall or winter.
Researchers are also comparing various tillage practices to determine if management can offer control solutions. Work is also underway to try to find out why the pests hit the outbreak area and how they spread. A probe of economic impact is also underway.