Protect your cacti by learning the telltale signs of plant diseases to which it is susceptible.
Cacti belong to the category of plants known as succulents, distinguished by their ability to survive in the hottest and most arid regions of the world by retaining large amounts of moisture throughout hot weather. If you live in such a climate and wish to grow cacti, a key part of maintaining their health is to know recognize the telltale symptoms of diseases that, if left untreated, can lead to serious health complications for your cactus plant. Does this Spark an idea?
Overwatering
As noted, cactus plants have evolved remarkable water-retention abilities. Partially because of this, homeowners can sometimes make the mistake of overwatering their cactus plants, particularly in the hotter months when some of the foliage starts to wither. Even if a proper watering schedule is observed, a soil that does not drain well enough can retain moisture and cause the plant's roots to become water-logged. If the soil in which your cactus is growing is moist to the touch, this is almost certainly what is causing the cactus to turn black. Back off your watering schedule; if necessary, replant the cactus in more well-drained soil and monitor the plant carefully to see if it grows back normally.
Lack of Sunlight Exposure
Because of cacti's proclivity for desert climates, they must bask in direct sunlight exposure in order to grow healthily. With the exception of shade-tolerant varietals of cacti, if your cactus plants are not exposed to enough sunlight, parts of the plant will turn black. To confirm if this is the case, you may need to replant the cactus in an area with more direct sunlight exposure and monitor it to see if normal growth returns.
Fungus Gnats
If the black spots on your cactus happen to be moving, the issue could be fungus gnats rather than any of the problems discussed previously. Fungus gnats tend to live in potting soil mixes, so infestations from these pests is more likely in the case of indoor, container-grown cacti. The most effective control method for a fungus gnat infestation is to repot the cactus in a pasteurized or sterilized potting mix; these mixes are treated for pest infestations prior to hitting the store shelves.
Other Possibilities
There are still some other possible diagnoses for your cactus plant turning black. If the black spots on your cactus occur near the base of the plant and are shiny in appearance and slimy to the touch, your cactus could be infected with slimy collar rot. If the spots were green and translucent with a sunken appearance before they turned black, the problem could be another disease known as glassiness. If none of these diagnoses explain your cactus's specific symptoms, have a university extension office diagnose the problem for you.
Tags: your cactus, cactus plants, black spots your, cactus plant, direct sunlight, direct sunlight exposure, replant cactus
