Mealybugs

Your infestation is likely mealybugs, especially if they have a cottony, fuzzy appearance and feel sticky. Mealybugs suck the nutrients out of the plant and will eventually kill it if left untreated. The black residue that you see is the result of the honey dew that the insect secretes. A mold then grows on top of the honeydew and that is called Black Sooty Mold. The sooty mold won’t harm the plant unless it is excessive and prohibits the plant from photosynthesizing. You could try to wipe the insects and the leaves off with a damp cloth dipped in alcohol and follow with a spray of insecticidal soap or pyrethrin by following the directions on the label. You can also spray with an organic control containing Spinosad that has a 7-10 day residual. Spinosad should be sprayed in the early evening after the bees have returned to their hives. Once the spray has dried, it is safe for beneficials.