Q: I have four Leyland cypress trees that are six feet tall. They all have little pods, containing some sort of worm, hanging from almost every branch. One of the trees died and the others aren’t looking too good. What should I do now?
A: Junipers, Leyland Cypress and Cedar Trees can be skeletonized by August if they have bagworms.
VERY close examination of a rapidly disappearing shrub reveals dozens of brown “bags” hanging from the limbs. The bags are made from the plant’s needles. They contain a wingless moth, who feasts on the plant’s greenery.
Unfortunately, once the bagworm is easily noticeable, it is too late to control the pest with insecticides.
At this point, there is no solution except hand removal. Wear a long-sleeved shirt to avoid being scratched by the needles and scales of the host plant.
Collect and destroy all cocoons. Despite their empty appearance, there are likely to be eggs in the bottom tip of the bag.
Make a note to spray Bacillus thuringiensis or a landscape insecticide three times at weekly intervals in mid-May, when the caterpillars have not yet formed their protective bags.
Pam and I have been the victims of these elusive destructive moths and due to their uncanny ability to be completely camouflaged, they destroyed a couple of beautiful, healthy Leyland Cypresses before we even knew what hit us. Prior to that we didn’t even know what a bagworm was, but we found out the hard way. Our advice is to begin closely inspecting your plants now to see if there are any signs and if there are take appropriate measures sooner than later. They are very destructive.