jamesrobertsmith wrote:Question: Is the chestnut healing over? If so, does that indicate blight resistance?
It could be. From my general reading on the subject (ACF literature), they say that healing cankers are swollen with fewer spore producing bodies. However they also say that there are different strains of blight out there, some more virulent than others.
From my own limited experience I have seen cankers briefly stabilize with swollen calloused boundaries, but then the blight can 'break out' again and still kill the tree. The canker in the picture looks to me like it is starting to heal, but I don't have enough experience to say for sure. I guess time will tell.
I read that the European chestnut recovered when a virus spontaneously appeared that attacks and kills the blight. Is this true?
I've read the same thing. They say it works in europe because hypovirulence arose soon after the blight itself appeared. As a result, the blight had less time to differentiate into different strains (as it has done here) making it easier for the virus to spread through the entire population of the blight. They also speculated that the European chestnut might be less susceptible to the blight than the american.