Q.Flies on Azalea Bushes
At my home I have several azalea bushes that are probably as old as the house itself (40-50). They have always been healthy and never had any problems. A few years ago they started to get lace bugs and had them for several years in a row. I treated the azaleas with an insecticide and the shrubs were fine. Last year I noticed what seemed to be common houseflies, which are slightly green in color, on one or two of the azalea bushes. This year I have a full blown infestation of every single one of my azalea bushes. Are these flies doing any damage to the plant, as I do not see any damage as of yet. Is this something I should be concerned about or something that is just a nuisance more than anything?

Certified GKH Gardening Expert
Those flies are telling you that your bush has another problem. The flies are attracted to the honeydew of other insects. Treat the bush with neem oil and this should help. Here is more information: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm