Q.What are deep dark crusted spots on Meyer Lemon Tree
What are the deep, dark crusted spots on my Meyer lemon tree? Skin penetrated but no sign of living pest.
As you can see from this article, http://idtools.org/id/citrus/diseases/gallery.php?page=1
there are many disease that could strike your Meyer lemon. The first defense against diseases is always a healthy plant; use this article to double check your cultural practices: https://www.gardeningknowhow.com/edible/fruits/lemons/growing-meyer-lemons.htm
I also recommend you take some samples of your diseased fruit, also any leaves that have spots on them, to the nearest county extension service, where they can analyze the problem and give you recommendation for treatment. This link will help you find the nearest office: https://www.gardeningknowhow.com/garden-how-to/info/what-is-extension-service.htm