Tie off the bag with string or a twist-tie. Collecting samples from woody plants. Cutting samples from the margin. That's all the special directions about woody plants. Vascular Wilts of Woody Ornamentals Dutch Elm Disease and Verticillium Wilt Remove recently wilted branches from the tree or shrub, but do not use dead and dried-up branches.
Infected limbs show vascular discoloration under the bark.
Isolation of the causal fungus is easiest from twigs showing sporadic streaking, but can still be accomplished when twigs show a solid ring of discoloration. Put specimens in a clean plastic bag, tie it off and refrigerate it until you can take it to your county Extension office. That's all the special directions about these diseases. Dutch Elm disease and Verticillium Wilt. The inner bark should still be fresh and green.