Diseased cacti. What is it? How to treat/prevent?
Here is possibly the worst case of this disease I have seen in my plants (on Echinopsis subdenudata). Many of my cactus plants have been getting this disease.
Some susceptible cacti: Leuchtenbergia principis, Rebtia heliosa, Echinocereus viridiflorus
Some resistant cacti: Astrophytum spp., Echinocactus, Parodia spp.
My Hoodia plants are also having similar symptoms. Most of my plants just get small brown spots all over. It seems to somewhat be from growing conditions, since some of my Echinopsis plants in other areas of my garden have symptoms only visible upon close inspection (not a problem to me). Has anyone seen this before and know what it is? It is my speculation that this is a fungal or bacterial disease.