Spider Mites on an conifer

Asked July 27, 2015, 1:12 PM EDT

I have a Japanese style pom pom tree in our front yard and I have an infestation of spider mites on it. I have sprayed with an insecticide I got at home depot that is supposed to be systemic and and also kills them on contact. It doesn't appear to be working as I believe new brown leaves are showing up after I have sprayed several times. Any suggestions as to how I can get rid of them before I loose the plant. Thanks for your help.

Howard County Maryland

1 Response

It has been a bad year for spider mites. Once the plant has a great deal of browning, it is dicey to spray the usual horticultural oi or soap because instead of the insecticide harming the insects, it goes into the plants through the myriad mite punctures and harms the plant.

Spray your juniper with a strong stream from a hose to dislodge the mites, but also to cool and moisten the tree (which spider mites don't like.) Keep your tree well-watered, too, now that we are going into the hottest driest part of summer. (About 1" of "rainfall" a week is what plants like.)

You can also try spraying with an insecticide containing spinosad, which the juniper should be able to tolerate better.