INSECTS AND THEIR CONTROL 237 



about the time for second application for the codlin-moth, 

 is valuable in the control of the curculio and a third spray 

 two weeks later should be made if serious injury is feared. 



348. Plum gouger (Fig. 120) is another snout beetle, 

 closely resembling the plum curculio. Its native habitat is 

 the wild plum of the Mississippi Valley and Rocky Mountain 

 regions. The injury to the plum is somewhat similar to that 

 inflicted by the curculio. 



The adult beetle differs in having no humps on the whig- 

 covers such as those which occur on. the plum curculio, and 

 it is also characterized by a longer snout. The beetle hiber- 

 nates during the winter, coming out in the spring when plum 

 trees are in bloom, and first feeds in the blossoms. The small 

 plums as they are forming are punctured by the snout of the 

 beetle and eggs are laid within the puncture. The larva feeds 

 principally inside of the pit of the plum as it develops. 



Control by means of a spray of arsenate of lead at the 

 strength of three 

 pounds to fifty gal- 

 lons of water may be 



effective. Fio. 121. Scale insects three mature Citricola and 



349. Scale insects one black scale. 



(Fig. 121). No pests on trees and shrubs do more injury 

 than the scales. These are all tiny sucking insects which 

 puncture the tissues of a plant with mouth-parts which 

 are adapted to sucking and which pump the sap from with- 

 in. Two general types are recognized by the entomologists. 

 One is known as the armored scale and the other as the 

 lecanium scale. The former secretes a scale which forms 

 a protective covering separate from the body of the in- 

 sect under which it lives. The lecanium type of scale 

 is protected by a hard shell which is not separated from its 

 body. San Jose scale is a good example of the armored type. 

 The black scale of California and the hemispherical scale of 

 the East are instances of the lecanium type. 



