They generally do not require a lot of maintenance. The bottom leaves will brown and die off as the Crassula grows, and this is normal. Be sure to remove these to keep the plant healthy and so that it does not attract pests like the evil mealy bug!
Mealybugs are the biggest pest threat to your succulents. They love to hide in crevices on your Crassula so be sure to inspect your plants regularly. If signs of mealy bugs appear in the form of a white cottony web or disfigured leaves, be sure to eradicate them immediately. These small white scale insects drink the sap out of plants and secrete honeydew that attracts ants. A Q-tip dipped in alcohol or a spray from an organic pest killing soap will do the trick. Read my complete post on mealybugs eradication here.
Aphids are less common but still a potential threat to Crassulas. Like mealybugs, they suck out the sap. If left untreated, they will eventually kill your succulent. Protect your echeveria by applying diatomaceous earth to the soil and neem oil to the succulent. Use insecticidal soap to control existing infestations.
Learn more about Mealybug and pest eradication here.
Crassula Diseases
Make sure you never let your Crassula stand in water or else the chances of root rot and other fungal diseases will increase. Root rot is caused by consistent moisture and can lead to bacterial infections. The good news is that it is easy to prevent. Avoid overwatering and use a well-draining soil.
Root rot is best caught early, so routinely check for rot on your Crassula. Rotted sections will be brown or black and mushy. The rot usually starts in the roots and spreads up the stem. If you find an infected part, you’ll have to remove it or else it will spread. After cutting away the rotted section, leave your succulent out of the soil for a few days so it can dry out and callous over. Repot in fresh well-draining soil and keep an eye on watering.
Crassula Sunburn
Brown spots may appear on your Crassula. These are most likely from sunburn. Move your plant out of direct heat to prevent further damage. Learn how to save your sunburned succulents here.