"It can. I have had good success with shaving it off the limb or leader down into the cambium and then sealing it with a pruning sealer. The prunin sealer is like a tar, spray on. This keeps light off the remaining root system in the wood and seemingly starves it. This applies to broad leaf mistletoe, not the dwarf, since it does have it's own photo synthesis process. The wound sealer probably does not help it's cause being a petroleum product.
Some complete limb were removed on this tree as they were too compromised and dying or dead. No targets were near the tree, so this process of shaving the compromised limb was acceptable IMO, which will leave the limb eventually hollow as the mistletoe dies out.
There will be more seeds that will sprout and some that have probably even rooted into the tree that are not yet sprouting due to the lack of water and the dormancy of the tree. These will be addressed every couple years with maintenance visits."
Good strategy re mistletoe control. Butch, the same works for Phoradendron sp. in LA (and NC). Not sure how bad the limbs will be hollowing out from the mistletoe, or how much that matters structurally tho.
Becasse (you like birds?), I saw some in Q. rubra near Bordeaux (not many trees in the city
) last Oct. It's nice to leave here and there on low branches for wildlife, but it can mess up the crown all right.
Here's a busted up maple with mistletoe b&a. I went back up and took some off that right hand leader afterward.