surface of the bark trunk, branches, or twigs : are numerous 

 minute greenish-grey scales like oyster shells about the same 

 size as the scars just mentioned (Fig. 3). The life-history 

 01 the insect which makes these scales is as follows : In its 

 youngest stage when just hatched from the egg, the pest is a 

 minute and active louse-like creature which runs about on the 

 bark seeking for a place to settle down. In this stage it may 

 also be carried from tree to tree by clinging to other insects or 

 to the feathers of birds. On finding a suitable spot it drives in 

 its trunk and begins to suck the sap, at the same time losing its 

 power of moving about, and forming on its " back " a little 

 scale as a protection. It is in this stage that the winter is 

 :>assed. Once fixed, scales of the female sex, though growing 

 in size, never move away again. In the case of the male, the 

 full-grown or adult form is a winged insect (Fig. 2) which 

 comes out from under its scale in early summer and flies away. 

 The adult female scale, after pairing with a winged male, lays 

 eggs from which hatch the young " lice " mentioned above, 

 the life-history being thus completed. There appears to be 

 but one generation in the year. 



Natural Enemies. The Oyster- Shell Scale is much 

 reduced in numbers by the attacks of its natural enemies. 

 One specially valuable enemy is a jet-black " ladybird " with 

 two red spots on its wing-cases (Chilo corns). This ladybird 

 beetle which feeds on the scale may usually be seen crawling 

 about on the trunks of affected trees and it is often very 

 conspicuous on warm days in March and April. 



Methods of Control. (1) When buying young stock all 

 trees bearing scales or showing the characteristic littlfe white 

 ^cars should be rejected unless the seller can guarantee that 

 the stock has been fumigated with hydrocyanic acid gas or 

 otherwise cleared of scales. 



(2) The scale insects can be killed by thoroughly washing 

 the trees in winter with lime-sulphur at winter strength made 

 according to the following formula: 



Lime-sulphur (1.3 Sp. Gr.) 3 quarts. 

 Water ... 10 gallons. 



The concentrated lime-sulphur (1.3 Sp. Gr.) solution may 

 oe bought ready-made. A strong paraffin emulsion or miscible 

 oil is also effective. 



(3) In orchards which are well sprayed against other pests 

 Oyster-Shell Scale seldom develops sufficiently to become 

 troublesome. Any of the washes used for clearing the trees 

 in winter at the same time check the scale, while summer 

 T vashes tend to destroy the young scales when settling down. 

 The freedom from injury by the Oyster- Shell Scale is one of 

 the benefits which the progressive grower can credit against 

 his spraying accpunt. 



