The jade plant (Crassula argentea) has thick, fleshy leaves and stems that grow into a massive trunk over time. It produces groups of small, white flowers. The plant is used as an indoor floor plant. It grows up to 3 feet high and 2 feet wide. It prefers full sun from a southern window and does not need a lot of water.
If a houseplant, including the jade plant, has root rot, the lower leaves turn yellow, wilt and eventually drop. Root rot is caused by soil fungi, which grow when the plant is over-watered or if the soil is not well-draining. Root rot starts at the feeder roots, then spreads through the root system in about seven days, eventually causing the plant to die. The infected roots are mushy and brown. Healthy roots are firm and cream-colored. When the roots become infected, nutrient and water absorption for the plant decreases. If you notice root rot early enough, you might be able to save the plant by repotting in new soil. Disinfect the pot by soaking it in one part bleach and nine parts water for a half hour.
Spider mites cause flecking, scorching and discoloration on the leaves of the jade plant. Eventually, the spider mite damages the plant so much that the leaves drop and the plant dies. The spider mite is one of the many types of arachnid and is very small. Its color is varied--from yellow and green to red and brown, depending on the species. It produces webbing on the plants. The webbing protects the mites and their eggs. Try to control spider mites by introducing lady beetles and predatory thrips (just two of the mite's natural enemies), wipe them off the plants or hose them off. Most pesticides kill natural predators of spider mites, but do not kill the mites. If the problem is too bad and you must resort to chemical control, be sure to use a miticide or an acaricide for spider mites, such as Orthene, Avid or Talstar.
Mealybugs are a type of scale insect, even though they are soft-bodied. They belong to the family Pseudococcidae. The mealybug is covered with a white, waxy powder. The two species of mealybug that are attracted to interior plants are the citrus mealybug (Planococcus citri) and the longtailed mealybug (Pseudococcus longispinus). The mealybug attaches its sucking mouth parts to the plant and sucks the sap from the plant, weakening and stunting the plant. The leaves of plants, including the jade plant, turn yellow and drop off. If the mealybug infestation is not controlled, it will eventually kill the plant. Control mealybugs with pesticides.