Mealybugs are technically a type of scale insect (mealybugs and all other scale insects are in the order Hemiptera), but when it comes to gardening, mealybugs are often separated out from other scale insects because mealybug females are motile (all male scale species have wings), while other scale females generally lose their legs. There are three families of scale insects: Coccidae (soft scales), Diaspididae (armored scales) and Pseudococcidae (mealybugs).
Mealybugs. Mealybugs are pale insects that look like ancient creatures, sort of like trilobites. They are oval-shaped with short filaments that may look like legs at first. These garden pests secrete a white powdery wax that protects them from predators while feeding on plants. They also lay their eggs in these secretions, so remove any white powdery material from your plants to prevent future mealybug pest infestations.
Scale insects. Other scale insects also have a protective waxy covering, and scale species can look different from one another. Most females just look like tiny bumps on the plant, and they usually do not move. Adult males have wings, but they only live for two days or so.
When and where scale insects become a problem. Most mealybug and scale problems occur in warmer areas where there are long periods between freezing temperatures (eggs overwinter during freezing temperatures, so you may see eggs in the wax secretions). There are some exceptions, so always be on the lookout for these common garden pests. These pests are most often found in moist areas (so be careful not to overwater your plants) and are common on houseplants.
Mealybugs and other scale insects eat the sap from your container plants and can transmit diseases between plants. Mealybugs are found on citrus plants, ferns, cacti, gardenia flowers, sunflowers, orchid flowers and more.
How to get rid of mealybugs and scale insects. These garden pests can kill your plants if you let them grow to plague proportions. Always nip an insect pest problem in the bud right away, as the problem may be harder to fix later on. Because of their protective waxy coatings, mealybugs and scale insects are difficult to kill with pesticides. To kill mealybugs and scale insects, wet cotton swabs with alcohol and touch each mealybug or scale insect with the alcohol. This will kill them or make them fall off the plant (make sure to step on them if they do fall off). You can also release natural predators of these pest insects, including parasitic wasps, praying mantises and ladybugs.
Scale Insect TIP:
Ants are usually found near mealybug and other scale insects because they “farm” them for their sweet honeydew secretions (ants also harvest aphid secretions). The ants also protect the scale insects from predators and parasites. Because ants are known to farm both scale insects and aphids, you may want to try keeping ants out of the garden as a preventative measure.