The root cause of your plant is hard to evaluate without a picture, but these reasons if your cactus is turning brown from the top, where the new growth is usually appearing, it might be infected with mites.
13+ Cactus Has Brown Spots. For instance, if your plant is turning brown from the top, the cause could be sunburn. Browning is a relatively common problem that many cacti gardeners have to deal with.
Cactus Has Brown Patches Help from i95.photobucket.com
Maybe you have and you just don't know it. While each cactus has different water requirements, there are a number of techniques you can use to larger cacti also have a a smaller surface area to volume ratio, which will decrease evaporation of the cactus will start to discolor. For instance, if your plant is turning brown from the top, the cause could be sunburn.
Its throat and breast are heavily spotted dark brown and black, and its wings and tail are barred with black, white and brown feathers.
Brown spots on cacti can be caused by a wide range of problems, but environmental issues are usually the culprit. Do you have brown spots on fiddle leaf fig leaves? I have observed both superficial fungal growth on the intact skin of cactus plants and plants injured or destroyed by fungal attack. Molded by dry desert climates, they don't require much water or care and can survive extreme weather conditions.
