25+ Brown Cactus Fungus. The over watered one is showing signs of rot or fungus , or it could be an infestation. Growing cacti is not really difficult and can be quite rewarding.
A year ago or so, my cactus started developing yellow spots all over and was diagnosed with a fungal infection.
The sun burned one is also having brown lesions spreading and both of them have. Fortunately, this is not a death sentence for your plants. If the cactus fungus is growing where a leaf has broken off, then you will need to cut off the infected area. Cut behind the infection so that you can throw the.