Question
Hi Jim:

It seems like overnite that my pussy willow tree - it is about 15 feet tall - has tight clusters of black bumps and what looks like lady bugs close by the clusters.  They are mostly in the center mid to upper branches.  Can you help?

Thanks,,Stephanie

Answer
Sounds like a scale insect probably willow scale. These insects attach to the twigs and suck the plant juices from the tree. They secrete a sticky substance called honeydew, which is high is sugar content. The lady bugs are the natural enemy of the scale and are feeding on the scale insects. You can control the scale insects with a soil applied insecticide called Bayer Advanced Tree and Shrub Insect Control. This is applied to the soil around the tree and watered in good. It takes a week or so for the roots to transport the insecticide to the twigs and when the scale sucks the plant juices they are killed. Here is a web link to this product. You should be able to get it at your local nursery. There are other insecticides that can be sprayed on the tree but these need to be sprayed for best results before the insect forms a scale (shell).  
http://www.bayeradvanced.com/product/Tree-Shrub-Insect-Control/concentrate.html

The more organic way to control scale insects is just let the ladybugs do their thing. As always the most green way to control scale insects is by their own natural predators. Ladybugs, soldier beetles and parasitoid wasps. Since they are there now and in some numbers I would let the ladybugs do the control for you and see if they can control the scales without the use of the insecticides. IF they do not succeed you can then treat with the Bayer product.