A tough succulent that loves sun and warm, dry weather, jade plant (Crassula ovata) grows with little maintenance and is rarely bothered by insects. Two troublesome pests may affect jade plant. Mealybug, rather than mealy worm, a tiny insect recognized by a puffy, cottony covering on the stems and leaves, damages jade plants by sucking the sap. Similarly, scale insects are destructive pests that pierce the leaves and suck the juices. Scale insects are covered by a hard, waxy, shell-like covering. Although jade is often grown indoors, the plant grows outdoors in U.S. Department of Agriculture plant hardiness zones 10 through 11.
Dab individual pests with a cotton swab dipped in rubbing alcohol to remove a light infestation of mealybugs or scale. Work carefully and as much as possible, remove the pests without dabbing rubbing alcohol on the leaves. Alternatively, remove the pests gently with a dry toothbrush.
Spray heavier infestations with a ready-to-use insecticidal soap spray product. Wet the plant thoroughly, including the tops and bottoms of leaves. This spray is an effective treatment of soft-bodied insects, including mealybugs and scale. If you buy a concentrate, mix the solution at a rate of 1 teaspoon of concentrate in 1 gallon of water. Reapply the solution every seven to 10 days. If your jade plant is a houseplant, take it outdoors to spray, if possible.
Fertilize jade once every three to four months during spring and summer, using an all-purpose, water-soluble fertilizer mixed at a rate of 1/2 teaspoon per 1 gallon of water. Do not apply more than this and do not apply fertilizer during the winter. Too much fertilizer produces lush new growth that can encourage infestations of mealybugs and scales.
Prune off heavily infested leaves and stems. Keep the infested plant away from other plants to prevent spreading the pests.