Major Scale Insects of Alabama Fruit

November 18, 2008

Two major scale insects of fruit in Alabama can be found in many peach orchards. The most common is White Peach Scale, Pseudaulcaspis pentagona and is easily recognized by the white scale covering secreted by the male giving a wooly/cottony appearance on the limb surface. This insect was introduced into the United States in the late 1800's. White peach scale will feed on numerous plants but is most commonly found on peach, privet, chinaberry, mulberry, and persimmon. We also find it feeding on kiwi at our Research/Extension Center.

White peach scale can have 4-5 generations per year in Alabama and numbers are able to build up guickly. Each female is capable of laying 100-150 eggs. Mated females will over-winter on trees and in early spring immature scale "crawlers" will emerge and spread out to new feeding sites.

In adition to white peach scale, San Jose scale, Quadraspidiotus perniciosus ,have emerged a a serious fruit pest. This scale can also build up numbers very quickly and unlike white peach scale will move out to green shoots and fruit. On fruit the young developing scale will cause "freckling" on fruit. Small reddish circular areas develop and can render fruit unsightly for marketing. San Jose scale is more difficult to detect on the tree and often will not be noticed until limbs begin to die or fruit become infested.

The backbone of management for both scales in peach begins with the end of the season peach tree borer spray(s). Insecticides used for borers are also effective on the crawler stage of the scale.

Following leaf shed from the dormant through delayed dormant period, one to two oil applications can be made for scale. Combined, these two practises will keep scale insect numbers from getting out of hand.

If you have let scales get out of hand you will need to make two dormant oil applications at least two weeks apart. Also plan to monitor for crawler activity.
Monitoring for "crawlers" can be accomplished by use of black electrical tape and thin coating of petroleum jelly. Timing of labeled insecticides can be targeted with crawler emergence.

For additonal information on white peach or San Jose scales read and follow the pest management guide for your particular fruit (return to Peach IPM home page)

White Peach Scale

San Jose Scale