|Hello, I have two azalea topiary plants in my courtyard. They have been attacked my aphids. The leaves, stems, etc. are all turning into this sticky black consistency. I've tried washing one with a leaf cleaner I got from the nursery but it seems like it killed off the rest of the green leaves. Can you recommend what I should do? Or is this a total loss?
|Answer from NGA
June 30, 2010
|The black coating is called sooty mold and it is a direct result of insect feeding. When aphids feed they excrete a sticky substance called honeydew which ages and turns black. It doesn't look very attractive but it doesn't really harm your plants other than to stop photosynthesis. Concentrate on controlling the aphids with insecticidal soap sprays and eventually the sooty mold will weather away. Good luck with your azaleas!
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