Ball moss is the grayish-green pincushion-like or tufted growth often seen on the bark of a number of Texas shade trees.
For those who scuba dive or snorkel in the Carribean, it also looks like sea urchins on the tree.
Ball moss is an epiphytic plant, meaning it derives its nutrition from the air, not from the tree. It causes a great deal of worry for homeowners who fear that the ball moss is killing their trees. Although trees heavily infested with ball moss have been observed to undergo a slow decline (because the moss can smother lower limbs of a tree simply through shading of buds), in general moderate populations of ball moss are not harmful to a healthy, actively growing tree.
If your trees have a heavy infestation of ball moss ... or you simply don't like the look of the moss in your trees ... there are effective control measures: Kocide or any Banner-based Funcide (those with propiconizol - PPZ).
When there is only a light infestation of ball moss present, just take good care of your trees by following the GardenLine-recommended deep root feeding techniques. And don't worry - no chemical sprays are needed. However, if large numbers are present, here's your ball moss battle plan:
1. Prune out and destroy dead or severely weakened branches, especially those encrusted with the moss.
2. Treat with fungicide. (Best applied February through June).
3. Deep-root feed following the tip sheet noted above.
4. Re-treat with fungicide in six months if the ball moss is still active.
When controlling ball moss using Kocide or PPZ, it is important that all the moss be covered and saturated with the spray. To be effective, applications must be made before or during the rainy season, usually, mid-February to early June. This ensures that the fungicide is on the ball moss and waiting to be absorbed with the next spring rain. Ball moss treated with Kocide will die over a six to 12-month period but will remain in the tree because of its "hold fasts." In most cases, it will take 18 months for these attachments to decay sufficiently so the moss drops from the tree.
Once Kocide has been applied and the moss is killed, it will become dark gray, and the leaf-like structures will point downward rather than be in an upright position.