THE OYSTER-SHELL SCALE. 



(Aspidiotus ostreceformis, Curtis.) 



FIG. 1. Oyster- Shell Scale (female), 12 times natural size. FIG. 2. 

 Oyster-Shell Scale insect (male), 25 times natural size. FIG. 3. 

 Oyster-Shell Scales in position on bark, 12$ times natural size. (All 

 after Newatead, Monograph of the British Coccidse, Bay Society, 

 1900.) 



This, scale insect, which lives under a shield or covering 

 somewhat like a minute oyster-shell (Fig. 1), is widely dis- 

 tributed in Britain and is a pest which should be known to 

 all fruit growers. 



Plants Attacked and Nature of Damage. The Oyster- 

 Shell Scale attacks plum, cherry, apple, pear, peach, apricot, 

 and nectarine. It has also been found on currant and many 

 other plants, among which heather may be mentioned. The 

 scale insects live on the trunk, branches and twigs of the 

 tree, sucking up the sap, in consequence the tree is weakened 

 and in exceptional cases where the pests are very numerous, 

 twigs, branches, and even whole trees may be killed. This, 

 however, is unusual in commercial plantations, and as a rule 

 the Oy slier- Shell Scale is one of the many pests which do not 

 cause obvious injury and in consequence are overlooked. 

 Nevertheless, such insects are worthy of attention, for they 

 never cease their attacks, and by draining away the sap impair 

 the vitality and fruitfulness of the tree. 



Description and Life-History. The most obvious feature 

 to be observed in the case of trees attacked by the Oyster Scale 

 is that the bark appears to be dotted here and there with small 

 white spots or scars slightly larger than a pin's head. Each 

 of these spots shows the position formerly occupied by a scale 

 insect which has died and from which the scale or covering has 

 fallen off. Close observation will then show that on the 



