The Hemlock Woolly Adelgid (HWA) is still an issue in the NC mountains. Untreated hemlocks continue to be infested with this tiny insect. For years, we treated Hemlocks with Imidichlorpid (Merit) by way of trunk injections or soil injections. A number of years ago, a newer systemic insecticide was introduced to fight the Adelgid. Safari is a very soluble product that can be applied to the bark of the tree, where it is absorbed through the bark and into the vascular region where it is transported throughout the tree. This has made treating hemlocks so much faster and easier!
The downside of Safari is that it only lasts 1 to 2 years in the tree. On the other hand, Merit Insecticide can last up to 7 years inside the tree. While Safari is easier to use, it requires an application each year. This spring, all hemlocks on the HCC Campus are being treated with Safari. Incidentally, given it water solubility, it gets in the tree in just a few weeks. This is perfect for trees with heavy infestations. Merit can take up to 6 months to be fully translocated throughout a tree.
