Grant supports affordable testing to fight Little Cherry disease – WSU Insider

Washington State University will help Washington State cherry growers test more trees for the noxious little cherry disease with a block grant for specialty crops from the United States Department of Agriculture. Washington State received by the Washington State Tree Fruit Association.

Named after its most distinct symptom – a small, colorless fruit – what growers call “Little Cherry” is a simultaneous outbreak of the Little Cherry virus-2 and disease X phytoplasma, both of which produce similar symptoms on cherry trees infected and are difficult to control. distinguish, even by experts. This is more difficult because symptoms are usually not noticed until a few weeks before harvest.

Pathogens are disseminated in orchards by small insects: the virus by mealybugs, and the phytoplasma by leafhoppers.

Tests are available to growers to find out if a tree is infected, but they can be expensive. The new $530,000 grant over three years will help expand the testing capacity of WSU’s Plant Disease Diagnostics Laboratory in Pullman with more equipment and supplies. This support will reduce testing costs by approximately 50%, to $50 per test.

“Affordable and available testing is a key part of our industry’s response to Little Cherry disease,” said Jon DeVaney, president of the WSTFA. “Washington cherry growers appreciate the support of the WSDA Specialty Crops Block Grant Program and the WSU Plant Disease Diagnostics Laboratory in this effort.”

“Active and aggressive tree removal is the best way to suppress this outbreak and prevent its spread, and testing is an essential tool for identifying trees in the early stages of infection,” said Scott Harper, virologist. of WSU and Director of Northwest Clean Factory Center. “This will help growers make informed management decisions for their orchards.”

Harper’s lab supported the first wave of testing in 2018-19, and commercial labs resumed testing in 2020, but few growers could afford to test every tree they suspected of being infected.

“WSU and collaborating labs are working hard to provide growers with testing services for Little Cherry,” said Tianna DuPont, fruit tree extension specialist at WSU. “Additional support for the WSU Plant Diagnostics Laboratory is essential to provide robust and sustainable public diagnostics so growers can quickly identify and manage the multiple issues attacking their trees.”

Prompt removal of infected trees is the best way to control the disease because there is no treatment and early removal can limit the spread of the virus to neighboring trees in an orchard, Harper said. Testing also helps avoid removing a tree that shows symptoms that look like the disease, but is not infected with small cherry pathogens.

WSU tree fruit scientists work closely with growers to fight disease and support Washington’s cherry industry, which produces more sweet cherries than any other state.

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