The Issues with Mealy Bugs
One of the biggest issues with this insect is they thrive and multiply at their peak when in a warm, dry environment with no ventilation...
– if that doesn’t describe every home !
Hosts
Most species of ornamental plants can be infested with mealybugs. But they will prefer those plants that have leaf axils or folds. A place to hide and breed !They also prefer plants with herbaceous or soft tissues – thus avoid things with hard outer skins like cactus , euphorbia, and even some palms – but you never know !
How they eat
Mealybugs damage plants by inserting their threadlike mouthparts into any part of the plant and sucking out sap. From this sap they filter out proteins and excrete the excess as a sweet, sticky liquid we call honeydew. Mold often grows on this causing infested plants to turn black.A few like the citrus mealybug also has a toxin in its saliva which causes its host plants to drop leaves and buds.
Citrus mealy bug
Where they hide
Mealybugs are usually found at the base of stems or petioles of plants. Nooks and crannies are their preferred place to lay eggs and settle down.
Clusters of eggs
Life cycle
Female mealybugs are soft and oval insects without wings. They are tiny ! – 3 mm long. Some species are covered with fluffy wax, while others have long tails of this material. It looks like cotton fibers.They don’t fly and must be transported directly to or near the next host plant. They can travel short distances by crawling or the very young nymphs may be blown about by the wind. In a home they are moved around by people touching the plants or dusting.In an evolutionary adaptation, some hitch a ride on the feet of birds, or jump on beetles to travel a far. This process is called Phoresy.Each female usually lays from 200 to 600 eggs in a thick ovisac. However, some give birth to live young. After several weeks, the nymphs develop into adults.Male mealybugs are also tiny - gnat like insects with four eyes, two wings and long tails of white wax. Male nymphs secrete a tiny, fluffy cocoon and develop into winged adults. Males then fly about seeking females to mate with.
Reproduction
Mealybug eggs are very small but and covered by a conspicuous dense, fluffy, white mass of wax called the ovisac. Very young nymphs are flat, oval and yellow. Older nymphs of some species are covered with fluffy white wax. The wax is impermeable to water making treating difficult.Small numbers of mealybugs are easily overlooked as they tend to wedge into crevices on plants. After the first batch of eggs hatch, the infestation becomes very noticeable. As their numbers increase, mealybugs of all sizes can be found crawling around or feeding on all surfaces of the plant.
Sooty mold
Control
Mealybugs are not easy to control. This is because the eggs are enmeshed in waxy fluff and thus relatively water proof. Likewise adults and nymphs can be covered in wax to varying extents and obscured in plant nooks and crannies where it is difficult to get thorough pesticide coverage.For a non organic chemical fix a systemic insecticides may offer the most reliable control because they make the plant toxic to feed on rather than relying on contacting the insect directly.For a more organic solution a contact insecticide based on soap or oil can be prepared and sprayed on. Repeat the applications two or more times a week apart. This helps kill nymphs that hatch from protected eggs and adults or nymphs that were protected by plant tissue. Wash and clean all surfaces after every spraying. Eventually you will kill the last remaining one !Keep an eye on the plants for a few weeks to make sure no mealybugs are overlooked.
Favorite place to hang out - an orchid flower axil !
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PLANT SPECIALISTSGREENING NEW YORK FOR OVER 53 YEARS !
Article written by our Staff Horticulturist, Peter B Morris, BSc, MSc, MBAAll photographs used with permission @SHUTTERSTOCK