Azalea leafminer larvae tunnel into leaf tissue to feed, causing brown blisters. Later, it emerges and rolls leaf tips around itself while feeding.
The azalea leafminer is a destructive pest of azaleas. Any azalea is vulnerable to this pest. Endemic to Japan, it has been introduced worldwide. In the U.S., this species is found from Florida to Texas and north to Long Island, New York, West Virginia and the Ohio Valley. It also is found in northern California and the U.S. Pacific Northwest.
In Southern states like Florida and Georgia, the larvae are found in every month of the year. However, infestations are most noticeable in nurseries from early spring through August.
Larvae tunnel into the leaf tissue to feed. Later in their life cycle, they roll leaf tips to protect themselves. As such, they are difficult to control with only contact products.
Photos: Larvae under microscope: J.A. Davidson, Univ. Md, College Pk, Bugwood.org; Ken Gray Image Collection, Oregon State University
Sources: North Carolina State University Extension, University of Florida
