Silviculture at Nettle Creek Farm

Eastern Hemlock Direct Injection Treatments (ongoing)

The Eastern or Canadian hemlock (Tsuga canadensis) is a common coniferous tree found throughout many east coast states, including Virginia. Unfortunately, the tree is highly susceptible to infestation by the Hemlock Woolly adelgid (Adelges tsugae) or “HWA”. The HWA is a sap-sucking bug introduced from Asia in the early 1900s. The HWA infestation has spread significantly throughout the Southern Appalachians. The bug appears as small white specks at the base of the tree’s needles.

There are limited treatments for HWA, particularly if the infestation is expansive. Chemical treatments are expensive and can be potentially harmful to the environment. However, small-scale treatment programs can be tailored by homeowners, even for a single or small number of trees. These treatments can take the form of cover sprays, soil injections, or direct trunk injections, depending on the particular location of the host tree. Additionally, these applications must be delivered by a certified arborist licensed to handle pesticides.

At Nettle Creek Farm we have a number of old growth hemlocks that are infested with HWA. However, these trees are located along the banks of Nettle Creek, a VA native brook trout stream which serves as a spawning tributary for the local watershed. The proximity of these trees to the creek limited our treatment options.

Enter Bobby Solar Jr., an ISA Certified Arborist and owner of Solar Custom Arbor Care in Covington, VA. (http://www.solarcustomarborcare.com). Starting in 2011, we began to design a treatment and pruning program with Solar Arbor Care whereby the chemical Imidicloprid would be injected directly into the trunks of 5 old growth hemlocks, thereby preventing any chemical from being transmitted into the nearby Nettle Creek, a VA native trout stream. Each treatment is effective for up to 3 years and must be maintained to prevent further infestation.

Our second treatment was applied in 2014 and so far, we are happy report a moderate level of success protecting these trees from the ravages of HWA.