Two pruning demonstrations have been scheduled this month to help orchardists understand how to prune Manchurian crab apple trees in order to be eligible to export apples to China.

The Chinese apple market, closed between 2012 and 2014 due to fruit infection caused by two postharvest rots, recently reopened. The two pathogens survive in the orchard on cankered twigs and fruit of Manchurian crab apple and cause commercial fruit infection in the orchard, which leads to development of speck rot and sphaeropsis rot in storage. The work plan for exporting U.S. apples to China requires Manchurian crab apple pollinizer trees to be pruned to qualify orchards for the export of apples to China.

Ongoing research has shown that pruning of diseased crab apples and drench applications of fungicides at harvest have effectively controlled these crab apple decays during storage. If growers regularly prune Manchurian crab apples in their orchard and appropriately apply fungicides, they should be able to reduce or eliminate financial losses due to these diseases. Fungicide applications provide additional protection from infection, but alone may not provide adequate protection. Pruning reduces sources of inocula in the orchard, which increases fungicide efficacy for control of these diseases.

Northwest Fruit Exporters, the Northwest Horticultural Council, the Washington Tree Fruit Research Commission, and Washington State University have organized the pruning demonstrations at the following locations:

—March 24, 10 a.m. at Herke Orchard, 14586 Summitview Road, Yakima (on the south side of Summitview, just east of Cowiche Mill Road).

—March 26, 2 p.m. at 5 Star Orchard, 19665 Road 5 SW, Quincy. From George, travel west on Frontage Road NW, turn left (south) on Beverly Burk Road S/Road R SW, turn right (west) on Road 5 SW and the orchard will be on the left in 1.8 miles.

For more information, contact David Anderson at Northwest Fruit Exporters, danderson@goodfruit.com, phone (509) 576-8004, or Parama Sikdar at parama_sikdar@wsu.edu, phone (509) 664-2280, ext. 207.