Dwarf mistletoe is an invasive weed that needs tackling right away. The sooner you catch it, the more chance you have of saving the tree as a whole. The benefit is the mistletoe affects branches, so you can cut off the infested branches to save the rest of the tree. How Mistletoe Kills Trees Mistletoe is a parasitic plant. It will steal all the food and water going to the tree. This prevents the trees getting the nutrients going to the tree, leading to them dying. The good news is mistletoe is slow moving unlike beetles. You have time to tackle the infestation without completely losing the trees. The problem is that the weed can end up spreading far away