In newly developed areas or in older established areas where trees are being replaced, the ideal method of controlling or preventing mistletoe is to plant trees believed to be resistant or moderately resistant to mistletoe. Avoid trees like Modesto ash, known to be especially susceptible to mistletoe infestation. Where many new trees are being planted, control mistletoe in any surrounding infected trees to reduce the infection of new trees. For treatment of existing trees it is important to remove mistletoe before it produces seed and spreads to other limbs or trees. Mechanical control through pruning is the most effective method for removal.
Growth regulators provide a degree of temporary control but repeated applications are required.
Severely infested trees should be removed and replaced with less susceptible species to protect surrounding trees. Using thinning-type pruning cuts, remove infected branches at their point of origin or back to large lateral branches. Infected branches need to be cut at least one foot below the point of mistletoe attachment in order to completely remove embedded haustoria. Done properly, limb removal for mistletoe control can maintain or even improve tree structure. In some cases it is best to remove severely infested trees entirely because they are usually a source of mistletoe seed.