Yesterday, when driving through the Slocan Valley in southern BC I noticed that a lot (in some areas most or even all) of deciduous trees (birches, apples and cherry trees for sure) look very, very sick. A friend who has a farm here told me that his cherry trees are all infested with thousands of little, green caterpillars. The caterpillars hang on the silk they produce and land on who/what-ever happens to walk close to the trees and this way, and by the wind, are carried from the infested trees to everywhere. I can't say if the infestation is the cause or effect of the disease. Does anyone know more about the problem? Here are pictures of the infested cherry tree leaf and the caterpillars.
I noticed our cherry tree had lots of clumps of brown leaves and was dropping many green leaves as well. I see this on many cherry trees and other trees in Vancouver and here at the garden. I have not seen quite as severe as you mention and don't know about the caterpillars, but I assume many plants are stressed and weakened by our very crappy spring weather. I expect we will be seeing a lot of pest and diseases this summer.
Tip blighting of stone fruits at this time of year likely to be brown rot. Unrelated species of trees liable to be displaying different conditions.
