Fungus spots on cactus pads are common. Black leaves on succulents are often a sign of 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. Treatment: Fungal … Black or sooty mold is a fungal infection often seen on plants that are also infected with pests such as whitefly or mealybugs. Too much water overfills the plant’s water storage tissue and causes it to bloat and explode. The most pressing of concerns with succulents is when you notice the stems are rotted. That can be fixed, so you don’t need to toss the plant and start again. You can see it in the picture here. See, succulents store extra water in their leaves, roots and stems so they can survive the arid conditions of their native desert. Fungus gnats are a really big problem on tropical plants because they thrive in that moist soil that tropical plants love. In a true fungal attack, there is a fungus growing inside the plant tissue that kills it as it goes. All you need is your trusted pruners to cut away the rotted part of the stem. Black or Sooty Mold. Answer: It’s possible the white powder on your Kalanchoe luciae “Paddle Plant” (or Flapjack) is actually normal, but it could definitely be powdery mildew too. If the plant is rife with lesions, it may be best to find some uninfected healthy material and start a new plant with a cutting. As you know, succulents are supposed to have a dry, gritty soil.It’s really not a conducive habitat for the fly larvae, so if you’re having problems, … The paddle plant naturally produces a powdery white coating that helps keep it healthy. The fungus does not harm or feed off the plants, but instead gets its nourishment from honeydew. It’s drowning. Usually the leaves will also feel soft and mushy. The honeydew or nectar produced by the pests attracts and feeds the fungus. It can also be a sign that the plant is sitting in the wrong potting mix. Sooty black mold is a fungus that can appear on the surface of plant leaves, stems, twigs, branches and even fruits. Rot is sometimes a fungus "eating up" the dead plant tissue, but in that case something else triggered the start of tissue death. The black spots are a fungus … The fix for black stem rot is to repot the plant. If the leaves are turning black, that means the succulent is rotting from the root up due to too much water. How to Revive a Succulent with Black Stem Rot. 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. How to Treat Fungus on Cactus. If damage isn’t severe, a fungicide spray can usually help. Honeydew is a sticky, sweet substance that certain insects secrete. Once there is a fungus affecting your cactus, it can be difficult to stop. This is what makes it turn brown and dry.