Mealybugs

Mealybugs have oval bodies with overlapping soft plates and a cottony white covering. They are related closely to scale insects, but do not attach to a plant and can moved around very slowly. They can stunt a plant or kill it by sucking its juices. They excrete a honeydew which can cause a black, sooty mold.

Control

Note that mealybugs have a symbiotic relationship with ants, which may need to be addressed to clear your mealybug infestation.

By hand

Mealybugs are serious houseplant pests around the world, and outdoors they are troublesome pests wherever winters are mild. When you spot an infestation, indoor or out, you can just dip a cotton swab in rubbing alcohol and dab the mealybugs directly with it by hand.

By hose

You can hose off plants every 2 weeks with jets of water (or insecticidal soap) in order to blast away as many of the mealybugs and their eggs as possible, as well as the black soot which deters natural predators.

Natural predators

Ladybugs (Ladybird beetles), cryptolaemus beetles and lacewings all are natural predators of mealybugs. They can be bought commercially and released to help control the population.

Chemical control

Chemical pesticides known to be effective against mealybugs include malathion, diazinon, acephate, or horticultural oil.

References

• Sunset National Garden Book. Sunset Books, Inc., 1997. ISBN 0376038608