Question
I have a maple tree over 30 yrs old and the branches have white cotton balls on them and leaves are falling off like it is fall and it is July..is this a disease and what can I do?  Thank you for your help...Linda

Answer
Sounds like cottony maple scale.

The cottony maple scale, Pulvinaria innumerabilis (Rathvon), is a highly modified insect pest that commonly attacks silver and red maples. The scales are usually first noticed when the females produce an egg sac which appears as a 1/4 to 1/2-inch long ball of cotton. Heavy infestations can result in branches being turned completely white with the egg sacs. Like most scale insects, the nearly mature insects, the adults and the eggs are resistant to pesticides and the anxious tree owner must wait until the correct time for management.

Normally, this scale is a mere curiosity and nuisance. The white egg sacs easily attract attention and the developing scales produce honeydew. Honeydew is the excess water and sugar excreted by many plant sap-feeding insects. Honeydew is commonly mistaken for "plant sap" being dropped on cars, sidewalks and lawn furniture lying under trees. When honeydew collects on leaves and branches, bees, wasps and ants are attracted to the area. If the honeydew is allowed to remain, molds called "sooty fungus" grow on the material, turning the surface a gray-black color.

Occasionally, heavy outbreaks of this scale occur, usually on weakened or stressed trees. These outbreaks can cause the death of numerous small branches and occasionally the death of a tree.

This pest has numerous parasites and predators that normally keep its populations in check. However, every few years, these natural controls seem to fail and the cottony maple scale can reach epidemic proportions. Unfortunately, weak trees can be severely damaged during these outbreak years. Healthy trees often loose a few small branches and have no apparent long term problems. What makes management of this scale more difficult is the fact that insecticide applications may actually cause the scale problem to continue longer than normal. This is caused by poor timing of a pesticide application that kills most of the parasites and predators but allows survival of the resistant scale stages.

Maples in restricted street lawns or suffering other stresses from drought, compacted soils, poor fertilization, etc. are the ones most likely to exhibit major branch or crown dieback. Improving the tree growing conditions will significantly help the trees survive the cottony maple scale attacks until the natural predators and parasites build up to effective levels. The most important predators are several black lady beetles that have two red spots on the upper surface.

Imidacloprid (Bayer Advanced  Tree and Shrub Insect Control)  is applied as a drench around the root zone of infested plants. This water soluble insecticide is taken up by the roots and transported to the twigs and leaves and when the scales suck the plant juices from the plant they are killed.  This provides a means of scale control without reliance on sprays. However, it may take a couple of weeks for the insecticide to reach the tree top.

Here is a web link to more information and pictures of this insect.

You could use spray type insecticides IF you can reach the area that the cottony scale is on. In this case use an insecticide called Orthene. But most large trees can not be sprayed due to the size.

Here is a web link to information on the Bayer product. Check with your local garden type store for both products.  http://www.bayeradvanced.com/tree-shrub-care/products/12-month-tree-shrub-insect...