QuestionThanks for taking my question. Last year I had a lot of flies on my Holly bushes. I used seven to get rid. Of the flies . I had a lot of leaves to turn black. This year on the back of the black leaves are white spots about 1/4 inch long . Can you help with this problem .
Thanks George Thompson
AnswerIt sounds like you have aphids. These small insects produce a sticky substance called honeydew. It is very sweet and insects like flies are attracted to it. The black substance is sooty mold which grows on the honeydew. If you control the aphids, both the flies and sooty mold should go away.
Aphids are usually more of a problem in the spring and they grow/reproduce rapidly. You can start by washing the plant with a strong stream of water to dislodge the aphids. This will help reduce the population to begin with. Then, wait for the plant to dry before applying one of the products listed below. If you want to keep the aphids off, you will have to spray every 10-14 days (see label) to keep control. I would recommend that you start with a more aggressive product (acephate, acetamiprid) and then once the population is reduced and you just have new babies to control, you can use one of the milder products (soap, oil). Again, repeated applications are going to be needed. Once you have the problem under control, you can monitor the plants daily and treat when aphids are observed.
Listed below are a few products available to homeowners. You should be able to find at least 1-2 at your local garden center. Other products not listed may also be available in your area. Be sure to read the label for mixing instructions and additional information about applying the product.
acephate plus fenbutatin-oxide Ortho systemic insect killer concentrate
acetamiprid Ortho max flower, fruit and vegetable insect killer rtu
insecticidal soap Safer insect killing soap conc.
malathion Green Light 50% malathion insect spray
neem oil Safer bioneem or Bonide Bon-Neem
