Sago palm trees are low-growing trees that reach a maximum height of only about 20 feet. They are slow-developing trees common to subtropical climates. Sago palms will often be attacked by various pests and diseases, such as scales, which try to steal nutrients off their hosts and can be potentially lethal when left untreated.
While sago palms originated throughout Asia, including Thailand, Japan and southern China, the scale disease did not affect sago palms on a large scale until importation, when it spread throughout the warmer climates of the United States.
Scales are parasitic insects that steal the resources from their host tree's leaves and organs.They attack the palm's leaves, roots and trunk. As the tree loses resources, its leaves will begin to wilt and it can lose the ability for proper photosynthesis. The additional loss of nutrients and minerals can become lethal when left untreated.
Scale damage on sago palms first appears as small white spots on the leaves. The insects will feed off of the underside of the leaves, damaging the surface, and cause yellowing or browning to develop in the structure.
Weather is the most common contributor to the rapid spread of sago palm disease. The wind and rain will carry insects from plant to plant. Female scales are almost always immobile, and remain on the plants to reproduce.
Scales are resistant to pesticides due to their waxy coverings, but can be treated in other ways. The application of horticultural oil will smother scale insects and cause them to suffocate. Biological treatments such as introducing predatory beetles or parasitic wasps into the environment will rid the tree of scales.