Scale Insects Are Harmful to Fruit, Nut, Shade Trees

The number of generations annually, date of hatching and other life history habits vary with the species, season and location. Each of the species of scale, however, can be controlled.

Detection

Often the scale infection will not be notice because of the fact that it is small and may appear as merely a brown lump on a small twig or as a white speck or spot and is not detected until the plants begins to lose vigor and portions die. Adult scale insects form a protective layer of wax over the body. This wax forms the scale, which may be in the form of plates or powder. Infestations build up primarily during the growing season and, as mentioned above, often go unnoticed until the plant is seriously damaged.

The female never move after once inserting the beak into the host plant. The male continues to move about, feeding upon the host. Eventually the male emerges from the protective layer he has secreted, form wings, males with the stationary female and dies. Soon the female deposits her eggs and after a short period of time dies also.

The tiny eggs soon hatch and the little crawlers or nymphs begin to crawl about the tree searching for a place to repeat the life cycle. Scales spread from plant to plant during the crawler stage on birds, insects, other animals and by the wind.

Oil Sprays

Dorman oil sprays are very in controlling scale insects. Oils are destructive to all three stages of the scale, eggs, crawlers and adults. This type of oil can only be applied during the dormant period of the year and even then should not be applied to evergreens. Another type of oil commonly referred to as summer oil has been used during the remainder of the year with some success. Summer oils are lighter than winter oils but may still cause serious foliar burn or death of the plant if extreme care is not taken in use. Use only the recommended amounts stated on the label when using either of these two oils.

Three other insecticides have been effectively used against most scale insects during the growing period of the year. Malathion, diazinon and cygon have given good control if applied while the nymph or crawlers are present. These insecticides control only the crawler stage of the scale. The adults are protected from these chemicals by their waxy scale cover and the chemicals have no effect on eggs which have been laid. When using these insecticides do no apply more material than is recommended. Use only on the specified plants listed on the label.

American Horticultural Society Pests and Diseases by Pippa Greenwood.