I've been seeing many wooly adelgid on my hemlock trees. What is the recommended treatment for this?
There is a systemic insecticide that works well in controlling this insect. The negative outcome from its use will be spider-mite outbreaks. The use of systemic insecticide should be made with caution. I find it effective on really tall trees that traditional sprays may not be effective in reaching or for really heavy infestations where a mass knock down of the pest is needed.
I would avoid using the "big guns" at first. There are predator insects that can be used in conjunction with milder insecticides like horticultural oil and soaps. The key to success is in the timing of the applications. I also suggest taking a soil sample to make sure that the trees have the right pH and nutrients needed to remain healthy. You can make an appointment to have an arborist take a look and provide you with suggestions for their care.
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