32 INSECTS AFFECTING VEGETATION 



of dead, dying, and injured deciduous forest and shade as well as 

 orchard trees known to be chosen as food by this species. (Ga. Bui. 

 44; Mo. Exp. Sta. 14; Bui. 47 Ariz. Exp. Sta.) 



The Fruit-Tree Bark Beetle.* Injury to the peach by the fruit- 

 tree bark-beetle is usually first indicated by the exudation of gum 

 from the trunk and branches, forming numerous globules, and later 

 by the presence in the bark of numerous small round holes, as if 

 the tree had been peppered with shot. As a rule, only trees in a 

 weakened or sickly condition are attacked, but injury to apparently 

 healthy trees has been observed. The insect causing this trouble is 

 a small cylindrical beetle, about one-tenth of an inch in length, and 

 about one-third as wide. Closely examined, it is seen to be uni- 

 formly black in color, except a portion of the legs and the tips of the 

 wing covers, which are dull red. 



In this country the fruit-tree bark-beetle attacks various vari- 

 eties of the plum, cherry, apricot, nectarine, peach, apple, pear, and 

 quince. 



The adult insects perish each fall, the winter being passed by 

 the larvae within the infested tree; and these transform to adults 

 which emerge from the tree usually about the latter part of March. 

 The adult beetles make minute holes through the bark, and they 

 and their larvae mine or burrow just beneath the bark thus destroy- 

 ing the cambium layer and killing the limb above. While the fruit- 

 tree bark-beetle is almost sure to attack first of all unhealthy, in- 

 jured or dying trees or parts of trees, they will attack and injure 

 apparently perfectly healthy trees. This bark-beetle is much more 

 difficult to control than other fruit-tree borers, but may be success- 

 fully held in check by careful attention to the following: Clean cul- 

 ture is of first importance; every tree or part of a tree that is badly 

 infested or is dying from any cause whatsoever should be removed 

 and burned at once. The trees should be kept in as healthy and 

 vigorous a condition as possible by cultivation and fertilization. 



We have found the best wash to be the following: Dissolve as 

 much common washing soda as possible in six gallons of soft water, 

 then dissolve one gallon of ordinary soft soap in the above and add 

 one pint of crude carbolic acid and mix thoroughly ; two pounds of 

 lime is then slaked in two gallons of water and filtered so as to re- 

 move all dirt and small lumps; this is now added to the above and 

 mixed; while to all is added one-half pound of paris green or one- 

 fourth pound of white arsenic, and thoroughly mixed. (Bui. 44 

 Mo. Exp. Sta, ; Cir. 29 B. E. U. S. Dept. Agr. ; Year Book, U. S. 

 Dept. Agr. 1905.) 



The San Jose Scale.~f. Probably the most serious single pest to 

 the deciduous fruits in this country is the Pernicious, or San Jose 

 Scale. A tree when badly infested with the San Jose Scale pre- 

 sents a somewhat grayish appearance as if it were coated with ashes, 

 but to the ordinary observer the tree would hardly seem to be in- 

 fested unless very closely examined. However, if one should at- 

 tempt to scrape the bark it would be seen to be covered with numer- 



* For illustration, see page 447. 



tFor illustrations, see pages G9 and 501, 



