Mealy bugs are off-white in colour and have oval flattened bodies growing to about 3mm long. Waxy strands that resemble legs occur along the sides of the body and some species also have a long “tail.” Normally they leave small cottony masses, their eggs, where the leaves join onto the stem. They like dark places so be sure to check under the leaves and well inside the foliage of a plant regularly. A severe infestation will cause wilting, discolouration and stunted growth of a plant.
Citrus mealybugs have been collected from at least 27 host plant families. Many ornamental plants grown in greenhouses are susceptible to attack including begonia, coleus, amaryllis, cyclamen, and dahlia. Citrus mealybug has been collected on canna, narcissus, and tulip outdoors.
They also excrete a sticky honeydew which could attract a black sooty mould. Another type of mealy bug lives on the root system of the plant in the soil. They suck sap from the roots and if the plant is left untreated it will eventually turn yellow and die. They can normally be seen in the water tray of the plant or on the surface of the soil.
Swab off the white cottony egg mass with an alcohol-soaked cloth. You may also wipe the whole plant carefully, but some plants will burn from the alcohol so test a small area first. Mist the insects with amild soapy solution and repeat if necessary on a weekly basis. For severe infestations, a systemic chemical would be most effective as this would be taken in by the insect rather than having to penetrate the mealy bug’s waxy coating.
For the root mealy bugs a granular systemic preparation is the most effective but be sure to water the plant well for a few days prior to use. These materials may be toxic, so follow the label directions very carefully You can also wash the roots of the plant in clear warm water and cut out the most affected areas. Discard heavily infested plants.