Needle miners are tiny caterpillars that feed inside pine needles. Needle miners cause needles to turn brown and drop prematurely.
Infested trees look unhealthy.
Persistent infestation may affect tree vigor. Chemical controls have been developed for high-value situations. Historically, needle miners have caused considerable damage to ponderosa pine foliage in several Colorado localities. Although needle miner feeding usually has not been serious from the standpoint of tree health, it is considered a problem because it detracts from tree appearance. This is particularly true where trees have high value, as in urban situations, or around homes in mountain subdivisions.