216 AGRICULTURE ON THE PACIFIC SLOPE 



very rapidly, and produce young which crawl about for twelve 

 to thirty-six hours, and then fix themselves to the branches 

 of orchard trees (apples, pears, and many others) and secrete 

 a shell of wax which completely covers them. They grow 

 rapidly, and in about a month produce others like themselves. 

 There are several broods in a year. Each female lays a large 



FIG. 123. A greenhouse scale (hemispherical scale) on a leaf. (Enlarged.) 



number of eggs, which lie hidden beneath the scale of wax 

 with which she covers herself. 



The most satisfactory spray for this scale is the lime- 

 sulphur spray, which is described on page 413. (California 

 Experiment Station, Bulletin 166; Idaho, 31; New Mexico, 

 68; Oregon, 38; Utah, 65; Washington, 56.) 



The cottony cushion scale. This scale at one time did a 

 great deal of damage, but is now kept in check by the Aus- 

 tralian ladybird (Vedalia), imported for the purpose from 

 Australia. 



Brown apricot scale. This does more damage upon prune j; 

 than upon apricot trees. The lime-sulphur mixture is not| 

 satisfactory for this scale, but it may be controlled by usingj 

 the resin compound described on page 412. (California 

 Experiment Station, Bulletin 16, 1905.) 



