Orchard Pests and their Control 381 



Insect Enemies of Plum 



Brown Mite. See under Apple. 



Howard's Scale (Aspidiotus howardi). There are a number 

 of forms of scale insects, none of the females of which have the 

 power of locomotion in the adult stage. In the group to which 

 Hpward's scale belongs the insects are incased in hard shells, or 

 scales, about one-sixteenth of an inch in diameter. They are 

 light to dark gray in color except that the raised, central point 

 is orange-red. They are inconspicuous, and trees are often badly 

 infested before their presence is discovered. A mass of eggs is 

 produced under the scales from which the young emerge through- 

 out the summer. These tiny insects crawl about for a few days, 

 then settle down and remain stationary during the rest of their 

 lives. They injure trees by sucking the juices. They resemble 

 closely the San Jose and the Putnam scales, and one is often mis- 

 taken for the other. Howard's scale is sometimes injurious, 

 but is easily controlled by applications of the lime-sulfur mixture 

 during winter or early spring. If it becomes necessary to spray 

 for them when the leaves are on, whale-oil soap should be used. 



Pear-tree Slug. See under Cherry. 



Plant-lice. Give the same treatment as for Green Apple 

 Aphis. 



San Jose Scale (Aspidiotus perniciosus) . This minute insect 

 is perhaps the most dreaded pest that has yet appeared in the 

 orchards of North America. So severe are its attacks that large 

 trees may be killed in from one to three years after being infested. 



This insect resembles closely the Howard scale, and for our 

 purpose the description of one will answer for both, as only an 

 expert can determine definitely the different species. It should 

 be mentioned, however, that the San Jos6 scale is not nearly so 

 particular in regard to its food plants, as it thrives almost equally 

 well upon the various members of the rose family, to which most 

 of our fruits, both large and small, belong. It may also infest 

 some of the forest trees and shrubs. 



Thus far, this insect has not been particularly troublesome in 

 this region, and, in fact, it has never been found in some of the 



