Just like in the coronavirus pandemic facing our communities, one of the challenges with the little cherry disease epidemic in Washington and Oregon orchards is that infected trees can be spreading the pathogens before the most obvious symptoms are spotted.

To get ahead of the disease, experts on the industry’s Little Cherry Task Force recommend strategic and thorough scouting for symptoms that may lurk on just one branch in early stages of infection, followed by testing and removal of infected trees as soon as possible. In fact, if prior testing confirmed the presence of the disease in the block, the task force now recommends removing all symptomatic trees right away, without waiting for lab test results. 

Little cherry disease is an umbrella term for symptoms caused by two different types of pathogens: the aptly named little cherry viruses and a phytoplasma pathogen that causes X disease. Both cause similar symptoms — unmarketable cherries with poor size, shape or color — and require tree removal to reduce inoculum spread by insect vectors. 

In the last few years, the task force, which includes industry, research and extension members, has learned a lot about how to scout and sample effectively for both the X phytoplasma and the little cherry viruses. 

To train growers and orchard workers on these best practices, as farms face their own human pandemic risks that prevent field days and hands-on trainings, Tianna DuPont and Bernardita Sallato from Washington State University Extension created a training video that covers the key points for scouting thoroughly, tagging and tracking trees, and collecting samples to send to the lab. A grant from the Washington Tree Fruit Research Commission supported the work and the Good Fruit Grower partnered with them to provide the videography. 

You can watch the video — available in English and Spanish — and find more resources for all things little cherry disease from WSU and Oregon State University at http://treefruit.wsu.edu/videos/scouting-and-sampling-for-little-cherry-disease/

by Kate Prengaman