WSU receives $195,000 grant to research apple aphids

The differences in how Washington apple growers battle pests in conventional and organic orchards may help Washington State University researchers decode the behavior of the woolly apple aphid.

Researchers recently received a $195,000 grant to study the behavior of the aphid in commercial orchards in the Wenatchee area and the Yakima Valley.

David Crowder, WSU assistant entomology professor, said there remains quite a bit researchers don't know about the pesky aphid, which can hurt the health of apple trees.

For example, there appears to be some evidence that applying pesticides can actually cause outbreaks of the woolly apple aphid, Crowder said. It's possible those pesticides eliminate the predators and parasites that help control aphids.

The aphids bore into the tree and suck out nutrients, he said. While they don't feed on the apples themselves, they can cause problems for the apple trees and impact the crops the trees are capable of producing.

The aphids also secrete honeydew, a sugary waste product that can encourage fungi growth, Crowder said.

Woolly apple aphids get their name from the fuzzy-looking barriers that groups of them form on apple tree limbs. That barrier is one that the aphid's natural enemies may not be able to get through, Crowder said.

Researchers will look at how the insecticide application decisions farmers make affect the aphids and their natural enemies, he said.

They also will look at how fertilizer use and other soil management practices affect aphid populations, he said.

Organic and conventional growers learn from each other, and many growers have both organic and conventional acreage, Crowder said.

The Washington Tree Fruit Research Commission provided funding to help get the woolly apple aphid research started this year.

Crowder said they have been collecting a massive amount of data from commercial orchards in the Wenatchee and Yakima Valley areas. The project would be impossible without the support of those farmers.

By the end of the three-year federal grant, he expects researchers will better understand what affects the aphids.

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-- Kristi Pihl: 509-582-1512; kpihl@tricityherald.com

This story was originally published October 12, 2014 at 8:55 PM with the headline "WSU receives $195,000 grant to research apple aphids ."