Ask the Expert: what would get the white fungus off azaleas , leaf the azalea has white on them , on the leafs is it a fungus , what can spray on them will mild soapy water work. Janet

Flower Shop Network Plant Expert Reply:

First we need to determine if you really have a fungus. Is the white substance powdery and can you wipe it off. If so, you have a fungus called powdery mildew. Soapy water doesn’t work on fungus. You will need a fungicide. Your local garden center will have a general purpose fungicide that will work for well on powdery mildew.

If the white on the leaves is more of a lacy pattern on the leaf that can not be wiped away, your azalea has been attacked by an insect called lace bug. Soapy water doesn’t usually control this type of sucking insect. However, if a more organic approach is what you want – try it. If it doesn’t work, you will need an insecticide.

You have two choices when it comes to insecticide control for lace bug – topical or systemic. The topical insecticides work more quickly, but won’t protect as long. Systemic insecticides are slow acting, but longer lasting. Your local garden center will carry both of these products.

Keep in mind, the damage caused by the insects will not change. The plant will produce new leaves and they will eventually cover the damaged ones. So, it is important to keep the lace bugs from attacking these new leaves.

If you would like to read more about the lace bug on Azaleas, the Clemson Cooperative Extension Service has a great article: Azalea & Rhododendron Insect Pests

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