SAN JOSE SCALE 145 



produced up to late autumn. And they are produced with sur- 

 prising rapidity. Investigations have shown that so rapidly are 

 the young produced and so quickly do they reach maturity, that 

 starting with a single female in the spring we might reasonably 

 expect that by the close of the breeding season there would be a 

 family of something like a billion, if there were no accidents. 

 Fortunately there are many accidents, but, even so, the rate of 

 increase is tremendous. This " continuous performance " in 

 production means that while the grower may clean up the trees 

 in the early spring and have relatively few live scales, yet if he 

 leaves any at all, he may expect that by autumn the trees will 

 be in bad shape again. 



Attacks Many Kinds of Plants. The third difficulty in keep- 

 ing the scale down comes from the fact that it feeds on so many 

 different trees and shrubs. The orchardist may get it out of 

 his apple trees, but an adjoining currant patch or some Japanese 

 quinces or thorn trees or dog- woods on a neighbor's lawn, or 

 even willow trees along the brook, may furnish a new source of 

 supply. It is therefore a constant fight in a scale neighborhood. 



Hard to Recognize. The first point in this fight is to learn 

 to recognize the pest. The easiest way to do this with apple 

 trees is to watch the young apples as they develop. The young 

 scales seem to be particularly partial to the fruit and are espe- 

 cially conspicuous on it, so that if there are any great number of 

 scales on the trees one is sure to find them sooner or later on 

 the apples. They usually collect at the blossom or calyx end of 

 the fruit, and frequently, though not always, produce a bright 

 red spot, the scales themselves varying in color from nearly 

 white on through gray to practically black. One will therefore 

 find a white, gray or black central speck surrounded by a bright 

 red ring. The scale itself is easily scraped off, leaving the red 

 ring with a light center. On the twigs and branches the appear- 

 ance is frequently described as resembling ashes thrown upon 

 the tree, and this is as good a description as can be given. The 

 bark will be roughened, and on scraping it with the thumb nail 

 or the back of a jack-knife a wet, yellowish streak is produced 

 by the crushing of the insects. Also if the observer cuts into 

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