Answer: Based on your description I am not certain which pest is attacking your mugho pines. I would suggest you work with your local county extension to identify the pest and based on knowing that, determine what to do next. If it is something that can be treated, they will have the most up to date information on what to use and how/when is best to apply it for maximum results. For example, if it is something such as pine weevil, any spraying needs to be done in the spring. At this point, corrective pruning would be the only step you could take. So please consult with them to get a specific identification of the pest so you can treat for it correctly.
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