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Getting Rid Of Insects In Locust Trees


I have 2 locust trees around 20 years old in my yard. I have had them trimmed twice as they are quite large. I am noticing that there are a lot of dead branches now on both trees. I am assuming some insect or fungus is attacking them causing foliage to cease and limbs to dry out.


I found a systemic liquid by Ortho, which has to be diluted and sprayed and is toxic. The trees are too high for me to spray and I would prefer not to do this as I have lots of flowers and grass underneath them which could be damaged, along with pets who roam the yard.

Does anyone have any suggestions to handle this problem short of contacting a professional, who I am sure is going to want to spray. Thanks for any advice you can give me.

Hardiness Zone: 5a

mtm from Northeast PA



Before you can take any productive action, you really need to find out exactly what you are dealing with. In order to find out you may need to either call in a professional, or contact your local county extension agency to find out if a Master Gardener would be willing to look at a sample and help you with the diagnosis. Insect and fungus attacks are quite different and require very different strategies for treatment. The Ortho you found may prove to be ineffective depending on what the problem is. Once you find out exactly what you are dealing with, you can research some Organic treatment methods that may or may not involve some type of spraying.

What kind of Locust tree do you have? Do you see any evidence of sawdust? The Locust Borer is a common problem that affects Black Locust trees. Do you see sunken spots on the branches that are dying? Are the leaves turning brown but the twigs look fine? Dead branches here and there may indicate verticillium wilt. You can check for it by taking a sharp knife and slicing diagonally through a dead twig. Verticillium wilt shows up as brown streaks in the vascular system. Did you have a cold, wet spring and summer? If so, you could be looking at a fungal disease, root rot, canker, or leaf spot.


Good luck!

About The Author: Ellen Brown is an environmental writer and photographer and the owner of Sustainable Media, an environmental media company that specializes in helping businesses and organizations promote eco-friendly products and services. Contact her on the web at


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