I've had this cactus for almost 20 years. In the past year or two my cactus has come up with either a fungus or some kind of bug infestation. An oval patch about 5" long and 3" wide has kind of either dried out or eaten away at the side of the plant causing a sort of hollowing out of 1/3 of the thickness. The plant otherwise seems healthy and has the same kind of leaf growth in spring as always but if this hollowing out business keeps going on she'll soon topple over. If there is another cactus lover or plant person who can offer some advice before that happens I'd be really grateful. Here's 2 photos of her.
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