452 Report oe^ the Entomologists of thb^ 



noret, as quoted by Comstock, the male scales are oval and usu- 

 ally smaller than the females, measuring but 1 mm, in length. 

 But little is known of the life history of this species. 



We have seldom found this scale in the nursery. It may do 

 serious injury on large trees, however. A good illustration of 

 this is on one of the principal streets of Geneva, where most of 

 the English oaks, Querciis rohar, which line the streets for two or 

 three blockei on either side, have been either killed or nearly so 

 by this scale. So far as we know its only food plant is the oak. 



The San Jose Scale. 

 Aspidiotus perniciosus Comst. 



At present this is the most important of all the species of in- 

 sects which attack nursery stock. It is important, not only be- 

 cause of the injury to the trees which it is capable of doing, but 

 because nurserymen and fruitgrowers are afraid of it, and hence 

 hesitate to buy stock from a nursery in a locality where the scale 

 is known to exist. It is also of especial interest, to nurserymen 

 and fruit growers in this State because it is being found each 

 season in new localities within our borders. The finding of the 

 scale in a small nursery near Union Springs probably means that 

 it has been sent to numerous localities within the State. Much 

 has been written about it and it has been described and its life 

 history written over and over again. Yet a very large majority 

 of the nurserymen and fruit growers of the State seem to have 

 but little idea of the true nature of the insect. It may be well, 

 therefore, to give a., somewhat detailed account of it in these 

 pages. 



History. — The original home of the San Jos^ scale is not posi- 

 tively known. Some writers think that it originally came from 

 South America while others believe that its native home may 

 have been Japan or possibly Australia. But wherever its original 

 home may have been it is said to have been known in the San 

 Jos6 Valley, California, as early as 1870. In 1880 Prof. J. H. 

 Comstock described it and gave it its scientific name. It was 

 not discovered in the east until 1893 when a few trees in an 



