A few weeks ago our Plant Healthcare Technicians spotted the first Japanese beetles of the season.
An adult Japanese beetle is about 12mm long. They have a metallic green, oval shaped body, with dark green legs and copper colored wings.Japanese beetles begin to emerge in late June. The adult beetles like to feed on tender new leaves, especially those of roses. Japanese beetles are attracted to dark foliage. A few common host plants include apple, hawthorn, plum, linden, birch, and some oaks and maples. The beetles will consume the tissue between the leaf veins, giving the leaves a lacy appearance. Heavily damaged leaves dry up and drop off. Adults will often be active on the host plants from late June through late July.
Although these beetles aesthetically can do a lot of damage and make the trees look bad, this damage is merely aesthetic and more than likely the trees and shrubs affected will grow back next year. To treat Japanese beetle infestations a chemical spray is used once the beetles are active and begin to cause damage to the host plant. A systemic insecticide can also be injected into the vascular system of the tree so that when the beetles come and eat the leaves they ingest the insecticide and die.
Another summer insect our technicians have started treating are Bagworms.
These insects hatch in June and will feed on trees throughout the summer. The more they feed the larger they become.
Bagworms can be found on numerous host plants. They are especially damaging to spruces, arborvitae and pines. The larvae feed on the foliage, leaving branches and plants defoliated. While feeding, each caterpillar spins a sac or bag around itself which it camouflages with bits of the plant it is feeding on. Often significant damage has occurred before and infestation is discovered.
If you notice a light bagworm infestation on any of your trees or plants you can manually remove and destroy the bags. We begin chemical treatment for bagworms in late June/early July. Heavy infestations often require more than one spray.