Hemlock Woolly Adelgid Treatment

The hemlock woolly adelgid (HWA) is an aphid-like insect from Japan that has become a serious pest of eastern hemlock, Tsuga canadensis, in the eastern United States. Discovered in Connecticut in 1985, the Hemlock Woolly Adelgid has spread rapidly to both cultivated and forest hemlocks.

Signs & Symptoms of Hemlock Woolly Agelgid

Even though the woolly adelgid is as small as a speck of dust, it is easily recognized by the presence of a dry, white woolly substance that covers it and its egg masses. Infestations of the hemlock woolly adelgid can be detected early by periodically examining young twigs for the presence of the egg sacs. They are readily observed in the spring before the eggs have hatched. Keep in mind that remnants of old egg sacs may remain on twigs long after the eggs have hatched and the insect has been controlled. Early detection is very important because injury to hemlock may develop quickly. That is why periodic examinations are an important practice in the control of the Hemlock Woolly Agelgid.

Hemlock Woolly Agelgid Treatment & Control

Several insecticides are available that will provide excellent HWA control. Insecticides should not be applied on a preventive basis. Many of the hemlocks in Connecticut will not be infested and will not need treating. Controls should be applied only when HWA infestations are observed.

An excellent time to control an HWA infestation is from July through September after the eggs have hatched and the young adelgids are relatively unprotected. Summer oil and insecticidal soap have been found to provide excellent control with one application, provided complete coverage is made in this time period. Both insecticides kill only by direct contact. Thorough coverage with a drenching spray is essential for control. Dormant oil is effective for HWA control when applied in April to mid-May. It will also control scale insects and mites at the same time.

Contact Might Oak Tree & Lawn Care today to learn more about your Hemlock Woolly Agelgid treatment options.

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