Azaleas being eaten by little green worms have been infested with azalea caterpillars. Azalea caterpillars start their lives off as green worms that later turn black and yellow with red heads. Noticing green worms is both a blessing and a curse, because you've spotted them early enough before they can cause major damage but now you have to treat your pest problem.
Azalea caterpillars feed nearly exclusively on azalea plants. Female brown moths deposit up to 100 eggs underneath azalea leaves. Eggs hatch and larvae eat in clusters side-by-side on leaves. Because of their numbers, they can cause severe damage to azalea plants. Most of their damage occurs in August and September. Left unchecked or treated, you may find a dead azalea plant.
Azaleas infested with a high population of azalea caterpillars completely defoliate the plants. Even moderate infestations harm the azalea. As leaves are being eaten by the pests, the azalea plant loses its ability to properly photosynthesize from lack of foliage. When photosynthesis has been disrupted, the azalea plant becomes malnourished.
Bring a bucket full of soapy water over to your azalea plant. Hand pick the caterpillars off the leaves and dunk them in the bucket. Azalea caterpillars cannot hurt humans. Oftentimes, azalea caterpillars will rear up into the air when they are disturbed, according to the University of Florida. Do not let that deter your. You can also shake the azalea bush, making the caterpillars fall to the ground. Stomp them with your feet.
When cultural treatments fail, gardeners can use pesticides. A bacterial pesticide that contains Bacillus thuringiensis should be applied to your azalea plant, according to the Georgia Center for Urban Agriculture. Gardeners prefer to use this pesticide, because it doesn't harm beneficial insects. Furthermore, pesticides that contain malathion or cyfluthrin may be used to kill off your azalea caterpillar infestation. Use the pesticides on dry days, so that the chemicals aren't washed off.