HOST PLANTS: Magnolia
DAMAGE:
These soft brown Magnolia Scale insects can kill trees if abundant. Feeding injury causes honeydew, sooty mould and twig dieback. The honeydew attracts bees, wasps and hornets.
DESCRIPTION AND LIFECYCLE:
They overwinter as partly grown young, and begin feeding in spring and summer. Young scales are small, flat and inconspicuous. Adults may be brown or mottled orange, with shallow wrinkles. The transparent coating of wax covering the body acts as a protective armour. By late August most of the females have produced nymphs that migrate to and settle on the new growth of a twig, where they start the cycle again. Depending on how badly infested a tree is, it could take several years to gain control.
CONTROL MEASURES:
1. Apply dormant oil in the spring or fall.
2. Apply Insecticidal soap, horticultural oil and approved insecticides during the crawler stage around late summer and early fall when the Mt. Ash berries turn orange. More than one treatment is advised.
3. On smaller trees the scales can be removed by hand scraping.
4. Maintain good health; Water regularly. Mulch the root zone. Maintain regular pruning, approximately every three years, specifically at the outer crown. Perform regular fertilization. (once scale infestation is under control)
References; Onnurserycrops Blog and Warren t. Johnson and Howard H. Lyon, Insects that feed on trees and shrubs