The characteristic symptom of exocortis is the shelling of susceptible rootstocks. Exocortis is spread
by a viruslike particle that kills the bark; the bark dries, cracks, and may lift in thin strips. Some
droplets of gum often appear under the loose bark.
It is best to remove infected trees because pruning clippers and saws, unless thoroughly disinfected
with bleach, can transmit exocortis to other trees. Some rootstocks may be less susceptible than others
tree infected with exocortis
shelling on susceptible rootstock