GARDEN INSECTS 



219 



it not for one pernicious kind, also a foreign importa- 

 tion, tliat now menaces tiie best horticultural interests 

 of almost the whole country. Every child who has a 

 garden should learn to know the San Jose, or pernicious, 

 scale, Aspidiotiis perniciosus. 



The San Jos6 scale takes its name from the place of its 

 introduction into this country, the San Jose valley, which 

 took place through the medium of trees imported from 

 Chili. Its original home 

 may be Australia, but in 

 spite of diligent search 

 this has not been fully 

 settled. It may have 

 come from China or 

 Japan. Three years after 

 its introduction this scale 

 was recognized as a dan- 

 gerous insect enemy, but 

 it had been widelydistrib- 

 uted on cuttings, scions, 

 nursery stock, and fruits 

 shipped to all parts of 

 the country'. 



The insect is minute and covers itself with a circular 

 scale from one to two millimeters in diameter, of an ashy 

 gray color, and with a minute prominence near the center. 

 If unchecked, its power for evil is almost beyond estimate. 

 The young are brought forth alive, and there are four or 

 five generations a year, so that it has been calculated that 

 a single female scale may be the progenitor of 3,216,080,- 

 400 during a season. This gives the plant no chance for 



Fig. 93. The San Josfi Scale 

 (Natural size and magnified) 



