What is the best way to protect a screening of Hemlocks from disease?
Wooly Adelgids and Fiorinia Scale on Hemlocks (Tsuga) can be controlled if caught at the early stages of infestation. During March, after it warms up but before the new growth starts, spray the entire plant with dormant oil. It needs to dry 2-3 hours before the temperature drops below 32 degrees. A second application may be needed and can be applied in June to early July at a 1 oz. Dormant oil to 1 gal. of water ratio (follow the directions on the bottle regarding temperature range for applications). The spreading rate is approximately 3.5 oz. per gal. of water on your applicator. It is important to get as close to 100% coverage as possible. This means you’ll need to spray up, under the needles. Dormant oil is organic and safe to use.
