Azaleas, which belong to the genus Rhododendron, are arguably the favorite flowering shrub of gardeners in regions where they will grow. While most produce an abundance of flowers that provide a bounty of color in the spring garden, many new varieties, such as the Encore Azaleas and Bloom 'N Again Azaleas, rebloom in summer and/or fall.
While azaleas are long-lived plants and very easy to grow, as with most other plants they are susceptible to visitation by insects, most commonly lace bugs, which can cause damage to plants. If left uncontrolled, lace bugs usually won't kill plants but the damage they cause is unsightly and can stunt plant growth and effect flowering if left untreated.
. To check for presence of lace bugs just look on the undersides of leaves. If lacebugs are present the plants will need to be sprayed with neem oil or malathion to eliminate these pests. make sure to spray both the top and undersides of leaves.
For season-long prevention and control of lace bugs and other leaf sucking or chewing insects a systemic insecticide drench containing Imidacloprid can be applied around the roots of the plants in late winter or early spring, when the azalea is in its spring bloom cycle or just when new growth is emerging. That said, many gardeners such as myself have stopped using neonicotinoids, such as Imidacloprid, due to concerns about the effects these chemicals have on honey bees and other beneficial pollinators.
Needless to say, I'd suggest spraying plants only if needed with neem oil, and at times of the day when bees, butterflies and other pollinating insects are not active. Alsoif at all possible, avoid spraying chemicals on open flowers
Important Note: Whenever using a chemical follow mixing and application instructions on the product label.