Question
I have a lilac bush (Mme Lemoine variety) that is continually plagued by something that I can't quite figure out.  The limbs get covered with patches of something white.  This does not look like scale (though it did have scale a few years back), rather a grouping of white fly, but they don't really fly away.  I keep spraying with Neem oil or an insecticidal soap, but this comes back periodically.  I am in the 2nd attack of this summer alone.  HELP !?

Answer
Alice, are you sure the white substance is composed of insects? The reason I ask is that lilac bushes are highly susceptible to powdery mildew. This disease occurs during damp or humid conditions. The primary control is a copper-based fungicide. I use an organic product called Soap Shield, which can be purchased through Gardens Alive. But there are many fungicides available at local garden centers that are just as effective.

If you have definitely identified the substance as a collection of white flies or other insects, you may want to resort to pyrethrum. This organic pesticide is a derivative of the chrysanthemum. It is non-toxic to humans and pets but highly effective against most insects. This product can be purchased at some garden centers or on-line through Planet Natural or Gardens Alive.

I hope this answered your question. Please write again if I can ever be of assistance.

Regards,

Mike