Stink bug threatens integrated pest management plans, researchers say
By DAN WHEAT
WENATCHEE, Wash. -- Scientists want growers to watch for the brown marmorated stink bug this summer which they say could devastate biological pest management in Central Washington tree fruit.
Two of the bugs were found in Yakima County last year, so far the only ones in Eastern Washington, but Washington State University entomologists say it's only a matter of time before there are more.
In recent annual tree fruit grower meetings, scientists have supplied growers with cards to help them identify the pest and asked them to watch for them this season.
"It's not a matter of if it will arrive but when," said Jay Brunner, entomologist and director of the WSU Tree Fruit Research Center in Wenatchee.
Called "The Beast in the East," it was identified in Pennsylvania in 1996 and is a problem in mid-Atlantic states, he said.
In 2010, some apple and peach growers in that region essentially lost entire crops to the brown marmorated stink bug, he said.
"The last couple of years they have learned how to manage it better but are spraying a lot in their orchards and still getting significant injury," he said.
A native of the Orient, it was found in Portland, Ore., in 2004, is established in host plants in the Willamette Valley and was found last summer on two farms in the northern Willamette Valley.
The pest uses more than 300 host plants, spreads by human movement and can complete its life cycle on fruit trees, Brunner said. It's been found in Medford, Hood River and in Vancouver, Wash.
It could become a problem for apples, pears, cherries, peaches, "you name it" in Eastern Washington, Brunner said.
His colleague at the Tree Fruit Research Center, WSU entomologist Elizabeth Beers, talked about the bug at the North Central Washington Apple Day on Jan. 22.
Brunner said Eastern Washington's hot, dry climate may hold it back initially but that it likely will adapt.
"I bet it will do well," he said. "There is some hope for biological control but it could set our IPM (Integrated Pest Management) program back 50 years is the threat. It could be a game changer for us."
A limited number of pesticides are effective against the bug, Brunner said. Growers will have to turn to broad-spectrum synthetic pyrethroids that have been avoided in apple IPM because they kill natural enemies that provide biological control of many pests, Brunner said.
Biological control will be lost, pests will develop resistance to the broad-spectrum insecticides "which will require additional insecticides and so on would go the pesticide treadmill story that started IPM in the first place," he said.
Only one carbamate, Lannate, is effective against the bug and it has very high human toxicity so growers probably will not use it, he said.
The USDA has identified a pheromone attractant for trapping that is being patented and is not yet on the market, Brunner said.
Light traps have been developed and may be used in early detection in Eastern Washington, he said.
A federal Specialty Crop Research Initiative project to find solutions is focused mainly in the mid-Atlantic, he said.