Can cold snaps, particularly strong north winds, in late spring during budding/leaf out cause a tree to develop pseudomonas? Or was the infection already there, the cold weather aggravating/accelerating what was inevitable? From late March through early May, we had weekly cold snaps - from the 70s/80s down to at or just below freezing, often with precip and strong north winds, and then back up to the 70s within the span of a week - and while I thought I had been diligent protecting my trees and bringing them in/out of the garage when necessary, obviously I either left them out too long or brought them back out too soon as I have definitely lost two trees, and quite possibly two more. All of my trees were sprayed twice with phyton 27, 2 weeks apart, shortly before bud-break. Of the two trees I hope to save, Shiro and Amagi shigure, I have severely pruned the affected limbs and thus far I have not seen the telltale black spot on the main trunk; I am keeping my fingers crossed on these two. I also sprayed them quite liberally again yesterday, after pruning, with they phyton. The other two trees, Shishi yatsubusa and Tequila Sunset, are beyond saving as they both have large black spots at the base of the trunk below the graft union. I'm saddened at losing my Shishi, but I am pretty devastated at losing my little Tequila since I don't know if I will ever be able to replace this tree now that Del has retired. Is there anything else that can be done to hopefully save the other two trees?