Answer: Unfortunately, based on your description, I am not certain which insect attacked your fruit. It might be apple maggots; these are the larvae of a fly type insect. You can control these by hanging red balls (coated with a sticky substance such as Tanglefoot) in the tree. Since I am not certain that is the correct pest, I would strongly suggest you work with your local county extension to identify the problem and based on knowing that, determine what to do. If a chemical spray is needed, they will have the most up to date information on what to use and how/when/how often to apply it for best results. Good luck with your plum crop this year!
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