Korchagin, V.N. 1987 [Diaspidids and coccids.]. Zashchita rastenii. Moscow (No. 3): 58-59.

Notes: Brief descriptive data are provided on various stages of the 3 commonest species among the diaspidids and coccids damaging fruit trees in the USSR, and short accounts are given of their food plants, bionomics, economic thresholds and control. The mussel scale [Lepidosaphes ulmi] is widespread on many trees. Each female produces 50-100 eggs, often parthenogenetically. These overwinter and are highly resistant to low temperatures. The nymphs feed on the bark. There is one generation a year. The polyphagous San Jose scale [Quadraspidiotus perniciosus] is the most dangerous species, particularly to winter apple varieties, and subject to quarantine regulations. It occurs in the south and in the Soviet Far East. The pest overwinters in the nymphal stage. The nymphs feed on bark, leaves and fruits, and there are several generations a year. A female produces up to 500 nymphs. Damage to the trees is widespread, and young trees often die. The brown scale [Parthenolecanium corni] is widespread and a particular danger to plum. The nymphs, which overwinter, feed on shoots and leaves. Each female lays 2000-3000 eggs. There is 1 generation a year in the north, but 2 or 3 generations occur in the south. For control, mineral oils are applied in spring while in summer these may be applied against crawlers of Q. perniciosus and organophosphates against these and crawlers of L. ulmi.