Liu, Z.M. 2004 [The control of powdery scale in the apple orchards in the western part of Henan province.]. China Fruits No. 5: 43-44.

Notes: In recent years the powdery scale (Pseudococcus comstocki) has become an important pest for apple orchards in China. The infected trees usually reach 2.3-9.7%, but sometimes reach 17.6%. Its first generation nymphs usually attack the young tissues of the tree, the second and third generation nymphs mainly attack the fruit. The bagged fruit could be attacked by 30%. The nymphs often cause yellow, white and green marble spot with red brown or yellow brown circles. It has three generations a year. Its eggs hibernate in cracks in the bark split or soil. The destructive period for the first generation nymphs is in mid- to late May. Practice showed spraying 1500x dilution solution of 40% Lorsban emulsion or 1500x dilution of 52.25% Nurelle-D505 emulsion in mid- to late May controls the pest.