Question
Our leyland cypress treeline around the inground pool is infested with
bagworms. They are slated for removal much to our dismay as they are to far
gone...My question is, what are the tiny round black objects covering the
cement, tons of them. I'm concerned that they might be eggs, if so how do we
get rid of them? This whole ordeal is a nightmare!!!

Answer
The tree may not be dead just the leaves are eaten off. This is what bagworms do and they seldom kill a tree. The "black objects" under the trees are from the bagworms--this is fecal material that is excreted when the insect is feeding. Control the bagworms and the "black objects" will go away. In the mean time wash the cement off is about all that can be done.

The common bagworm, Thyridopteryx ephemeraeformis (Haworth), is an interesting caterpillar. The most commonly observed form of this pest is the spindle-shaped silk bag camouflaged with bits of foliage, bark and other debris . Completed bags range from 1-1/2 to 2-1/2 inches long. The larva within the bag is brown or tan, mottled with black, and the bee-like adult males have clear wings and fur covered bodies. The females remain larva-like and do not emerge from the bag. The larva may stick its head and front legs out of the top of the bag to feed and move. When disturbed, the larva immediately pulls its head into the bag and holds the opening closed. Mature larvae may stay on their host plant or drag their bags some distance before firmly attaching the bag for transformation into the adult stage.

The bagworm occurs in the eastern United States from New England to Nebraska and south through Texas. The larvae seem to prefer arborvitae and red ceder but many other conifers and deciduous trees are attacked. These include: pine, spruce, cypress, juniper, willow, black locust, sycamore, apple, maple, elm, poplar, oak, and birch.

Mechanical control--If the trees are small enough to reach the foliage pick the bags off and destroy them.

Biological Control-Use the Bacterial Spray Bt The bacterium, Bacillus thuringiensis (Bt), is effective against bagworms if it is used against young larvae. Applications should be made at the end of June after all the eggs have hatched and the larvae are through ballooning.

Chemical Control-Insecticide Sprays Stomach insecticides are very useful for control of bagworms. Remember that the plant foliage is to be thoroughly covered because the larvae are protected from contact by being in the silk bag. Again, early sprays against young larvae are more effective than later applications. Products registered for bagworm control are: acephate (Orthene), bifenthrin (Talstar), carbaryl (Sevin), chlorpyrifos (Dursban),  diazinon, dimethoate (Cygon), malathion, nicotine sulfate, and pyrethrum.