For The Answer
By Calvin R. Finch, PhD,
SAWS Water Resources Director, and Horticulturist
Week of January 23, 2006
“Ball Moss on Your Trees”
The leaves have been off the pecans, red oaks, cedar elms, and other deciduous trees for awhile. Soon, the live oaks leaves will fall. When they do, many folks will notice that their trees have ball moss. Not to worry, ball moss is not a parasite or a threat to your trees in any way. Ball moss is an epiphyte, which means it makes its living from the air. In low areas with high humidity it can even grow on utility lines or fence wires. It likes the lower branches of live oaks because the crown forms an ideal environment with limited air movement. The branches on which it grows are not dead or dying because of the ball moss. They are dying because they are shaded by the branches above. Tree branches need a certain amount of light in order to stay alive. The light is necessary for photosynthesis in the leaves. Without light, leaves cannot produce sugars through photosynthesis and they starve.
If you do not care that ball moss is not hurting the tree, and just think it is ugly and want to kill it, there are several ways. It can just be physically removed. Ball moss is not attached to the branch very tightly. A cane pole or a pole and hook will remove all that you can reach. The usual way to control ball moss, however, is to spray it. The most legal and recommended spray is to use copper hydroxide, in the form of Kocide. Spray it on in February or early March and it will kill most ball moss on the tree. The clumps may not fall off, however, until it rains. Spray next year again to kill the clumps that survive the spray this year and the tree will be ball moss free for three or four years.
To reach very high in the tree you will need to rent a relatively powerful spray rig. Area rental stores have the rigs and will help you determine how powerful the sprayer needs to be based on the height of the ball moss. Follow the Kocide instructions carefully. The label is the law and tells you exactly how to safely use the material. It is relatively safe but can defoliate plants if it is misused.
In addition to Kocide many feed stores also sell baking soda as a ball moss control. Technically it may not be legal, but is often used at the rate of 60 lbs. Per 100 gallons of water.
In addition to ball moss area trees also have mistletoe and lichen. Mistletoe is a semi-parasite in that it penetrates the tree vascular system to intercept water and nutrients from the roots. A large amount of mistletoe growing on a mesquite or other tree can weaken the tree and especially the branch on which it is growing. The best way to remove mistletoe is with a pole and blade. The product Dormex kills the mistletoe leaves and stems, but it grows back within a year.
Lichen, like ball moss, is harmless. It is the papery gray green material that grows on the north or east side of the trunk. Lichen is a community of blue green algae and fungus that lives on the surface and collects moisture and nutrients from the air and rain. If your trees have lichen, rejoice, it means that the air in your neighborhood is relatively clean. Lichen does not survive in polluted environments. Kocide and baking soda kill lichen.
You are more likely to notice ball moss, mistletoe and lichen this time of the year because the leaves are off the trees. Raking leaves is good exercise and can be a rewarding way to enjoy the great winter weather in San Antonio, but do not send the leaves to the landfill. They are too valuable for such a fate. Use them for mulch or in the compost pile. Mulch over the roots of flowers, vegetables, trees and shrubs saves water and reduces weeds. Let leaves decompose on the lawn and they help restore nutrients to the grass. To speed up the decomposition, run the lawn mower over them.