The black spots won’t go away so just snip the leaf off (remember to sterilize your pruners). The cacti most frequently plagued by fungal lesions are Opuntia and Agave. Small spots, usually one-fourth inches or more in diameter, appear first. If you see large black spots, especially covering whole swathes of your plant, then its disease is already quite advanced. It is of some importance in commercial cultivation of Aloe vera. It impacts many trees, but doesn’t usually present any critical danger to them.. Black spot disease is a fungus that mostly attacks fruit trees like the cherry tree, walnut, grapevine, raspberry, blackcurrant, oak or red currant, certain shrubs like hydrangea and also vegetables such as cucumber, bean, pea, or tomato. Dark lesions that enlarge in size and deepen in darkness occur at the base of the stem and spread upwards. Identification to get black spots on succulents. Fungal infection; Mostly, the plants are affected by water warts and fungus in a warm area. These are fungal infection, sunburn, pests, frost, and overwatering. A few fungi types damage the roots and eventually, the whole plant, so once their visual damage is seen, it is too late for the plant. Once formed, the black spots are permanent and can be unsightly, but do not usually spread. If it’s a Jade plant, which is prone to developing black spots in the winter , the watering frequency needs altered because they don’t grow in the winter. But it’s not that easy to identify which black spots are caused by what reasons. Let’s say your cactus has been afflicted with either a fungal disease or an injury from freezing temperatures. Black spot disease is diagnosed when black or brown spots appear on leaves.. They hate humidity. Either way, it’s not looking so good. These fungi are mostly harmless, but they can ruin your arrangments by disfiguring succulents pretty severely. As with most succulents, ... Black spot is a common fungus somewhat unique to this genus and though it is rarely dangerous for the plant, mars them by forming large, circular black spots or depressions in the leaves. Identification to get black spots on succulents. Overwatering of succulents mixed with cool weather, or planting the succulent in the soil too deeply, provides a prime breeding ground for stem rot-causing fungi. Control with rose antifungal products. These may ooze brown, rusty, or black fluid, evidence of severe infection. Fungal lesions on cactus usually start as water spots or slight discolorations on the plant’s epidermis. Sunburned leaves; The succulents It is often quite impossible to diagnose which fungal organism is causing the spots, but often that is unimportant since treatments are generally the same. When it comes to fungi that cause leaf and stem spots, succulents have a wide tolerance. If you notice some shallow tan lesions on susceptible plants or permanent stippling or spotting, you shouldn’t use a fungicide. Unfortunately, there are many causes to brown/black spots on succulents. Leaf Spots. Charcoal Spot (fungus – Stevensea (Diplotheca) wrightii): Charcoal spot is a common and destructive disease of Opuntia in Texas. Pests such as mealy bugs, aphids or slugs, fungus, rot, burns from the sun, warts from too much water, the equivalent of frost bite, any puncture marks or scratches. Fungus spots on cactus pads are common. Nonetheless, we’ve tried our best to come up with the most relevant photos and descriptions for each of the reasons. Black spots on succulents are mainly caused by 5 reasons. Fungal infection; Mostly, the plants are affected by water warts and fungus in a warm area. It may be hard to identify what brown/black spot is … is a fungus that causes round brown or black spots on leaves of Aloes and Gasterias. The diseases can spread out from dry regions. The spots are surrounded by a ring of small raised dots that are the fruiting structures. One other thing to note is the type of plant affected by black spots. The succulent's leaves shrivel, and the succulent may die.