These three insects are very similar in appearance, having bodies covered with white or light grey waxy threads that appear fuzzy, like wool or cotton. These insects multiply rapidly, collecting by the thousands. This can turn a tree’s trunk, limbs or leaves white, as if covered by snow.
In instances where the leaves are attacked, they cause the leaves to curl inward, encasing themselves against certain insecticide sprays. Both conifers (pine type trees) and deciduous (leafy trees) can be attacked by these pests.
Injury to the tree under attack is caused by lack of sap. These insects remove massive amounts of sap, which is then excreted by the insect as ‘Honeydew’, a sticky, by-product of the insect. Dust and dirt in the air then adheres to this sticky substance and ‘sooty mold fungus’ forms, making the plant itself look unhealthy and personal items below it (such as cars, driveways, decks, patios, lawn furniture or children's toys) dirty and sticky. If the population of these insects are left to increase unchecked, severe decline and even death of the tree is possible.
As with any insect or fungus problem, the timing of applications and quality of products used are the most important considerations. Methods of control for Adelgids, Mealy Bugs and Wooly Aphids may include spraying, trunk injection or soil drenching insecticides. Treatment depends upon which insect is involved, the time of year, as well as the species of tree under attack. It is important to note that although these insects will die within days of treatment, it may take weeks or months for the shells to “slough off” and disappear from the infected trees.