Another year has passed and still no answer to what is causing AYLS!
Only a handful of new reports came in during 2017, all indicating AYLS is PRESENT except one personal observation that AYLS was ABSENT from arguta & deliciosa vines in Port Orchard, Washington. Those plants were in a hoop-house, possibly indicating that AYLS might be an Environmental problem rather than a Disease.
Two locations in Western Washington where the growers have consistently reported since 2014 that AYLS was ABSENT were refuted by personal observation that showed AYLS is PRESENT! Those observations now confirm that AYLS is PRESENT in all but about four locations reported from Abbotsford, B.C., Canada to south of Centralia, Washington. It is imperative that all people actually take the time to look closely at all vegetation on the vines before submitting a report. Many more reports are needed from around the World to obtain an idea of where AYLS is really PRESENT or ABSENT before an answer about the cause can be found.
One interesting observation is that AYLS emergence here in Seattle coincides with approximately 1,500 degree days as computed by the US.PEST.org website using a base of 41°F in this calculator for my local weather station (which may be reset using the Map function for a weather station in your area if you live in the USA and some parts of Canada):
Again, if you know of any Actinidia growers worldwide from areas that haven’t reported, please take the time to let them know about this site, and ask them to submit a Report using the form available on either the About AYLS or Map of AYLS locations Worldwide pages of this site.
Seattle, WA USA