All of sudden your azalea leaves start to lose their colors, become stippled, or even turn white.Iron deficiency?Need to be fed?What’s going on?
More than likely, this is the results of a very small sucking insect called azalea lace bug.Lace bugs cause leaf damage by sucking through their siphon-like mouth. If you notice spotted discoloration on azalea leaves, turn the leaves over. If it’s from the azalea lace bug, you’ll notice tiny black spots caused by the insect’s feces, as well as the skins of lace bug nymphs. The undersides of the leaves may also have a rusty appearance. If you find some, blowing the lace bugs off the foliage with several shots of a strong stream of water may be enough to lower populations early in the season. But as populations grow, insecticidal sprays are needed, and several are listed - horticultural oils, insecticidal soaps, Sevin, Eight, etc.Remember the sprays must hit the lace bugs, so spray thoroughly, making sure to get the undersides of the leaves where most lace bugs will be found. It may take more than one application, so check your plants again in a week or so to make sure they’ve been stopped.
Bayer or Bonide’s Tree and Shrub Insect Control can also be applied around the base of the plant, and will systemically help give your azaleas season-long control of lace bugs. It takes several days to move throughout the plant, so is best applied early spring or early fall, but can be applied in season.In heavy lace bug populations, a combination of sprays and systemics may be needed. It is also recommended to keep those azaleas as healthy as possible, with a couple spring feedings (after they flower), as well as watering thru the season, as needed.