Leafminer problem

Credit: jeridu/iStockphoto

leafminer_1.jpg

Q: For the last three years, I have had an infestation of little bright green worms that act like caterpillars on my Honeysuckle Azalea. They defoliate the branches and may have actually killed some branches. To control, I have shaken the plant vigorously (that is when I saw what they were) and sprayed with the hose. I have also sprayed the bush with insecticidal soap. This product really stirred them up. I hope this will do the trick as I do not want to use bad chemicals on my plants. The critters are bright green about 1/2 inch long with black heads, crawl and chew like caterpillars. They seem to have only attacked this azalea which is deciduous. What am I dealing with and how do I control this?

The insect is called azalea leafminer (Caloptilia azaleella) and it is common in many deciduous azaleas. This insect starts out as a leafminer, creating irregular blotches on the leaf as the larvae tunnel through the life. As the insect matures it abandons its leafminer style and becomes as a leafroller. As the insect begins its next cycle, it rolls up in the leaves before entering pupation, eventually emerging as a small moth. If only a few leaves are damaged by leafmining, just squeezing the leaves may reduce the severity of the damage. Ensure all fallen leaves are removed for disposal into the garbage (not in the compost) at the end of the season. The larvae pupate in leaf debris. There could be two generations each season. Low-growing azaleas tend to be more susceptible to insect attack.