what causes spots on ric rack cactus plant?
Hi! Could you share a photo, please? It’ll help to better recognize the problem.
It could be a Corky scab, which is also known as edema. If this is the case, you can see bumps, blisters,or scabs which look like a cork and have a woody texture. Amoung the causes is the reaction to biting insects, or the accumulation of water outside the plant’s vascular system. Moderate watering should help in treating corky scabs.
One more idea, if the spots are yellow or brown they could indicate that the plant gets too much light, so just move into a spot that gets less light.