The Bronze Birch Borer. 147 



In New York State this borer now occurs in destructive numbers in 

 St. Lawrence county, and in the following cities : Buffalo, Rochester, 

 Ithaca, Hornellsville, and probably others. The beetles have been taken 

 in other parts of the State, and it is liable to appear in destructive 

 numbers wherever white birches are used as ornamental trees. 



In Europe two similar borers {AgrUiis bctulcti Ratz, and Agrilus 

 viridis L.) are destructive to birches. 



The fact that the bronze birch borer often kills large trees in three 

 or four years is sufificient evidence of its very destructive character. 

 Within a few years many white birches in Chicago, Ann Arbor, Detroit, 

 Buft'alo, Ithaca and other cities have been killed by the insect. A tree 

 usually succumbs within two or three years after the first top branches 

 die. 



In 1895, AI. F. Adams, a keen observer of insect life, discovered 

 that the common white birches in Buffalo's parks were injuriously 

 infested by a borer. By 1898, several trees had been killed, the cut- 

 leaved varieties also were being attacked, and the culprit was found to 

 be the bronze birch borer. I saw in Delaware Avenue Park in Buffalo 

 on May 11, 1899, at least one hundred magnificent white birches, some 

 of them veritable monarchs nearly two feet in diameter at the base, 

 all dying from the work of this borer. In August of the same year, 

 Mr. Adams reported that from one spot in one of Buffalo's parks he 

 could see fourteen black and yellow birches, but twelve of them were 

 dead, all killed by this borer. Chamberlain reported in 1900 (Scientific 

 American, Vol. 82, p. 42), that the result of the work of this insect is 

 that " nine-tenths of Buffalo's white birches are either dead or dying 

 and the rest will soon follow. S'everal hundred have died, including 

 about 50 in Forest Lawn Cemetery the present season. Even the dead 

 trees were not burned, and the pests were allowed to multiply at will." 



I have seen over half of the white birches on the Cornell University 

 Campus and many of those scattered about Ithaca's lawns killed by the 

 insect within the past three or four years. And unless the vigorous, 

 prompt, and judicious measures now being enforced on the Campus are 

 carried out throughout the city, Ithaca's white birches will soon be dead 

 monuments to the industry and destructiveness of this little enemy. 



Food-Plants or Kinds of Trees Attacked. 



This insect seems to confine its work almost entirely to birch trees. 

 The only exception yet recorded is discussed on page 146 where it was 

 found making gall-like swellings on a willow. The European white 

 birch (Bcfiila alba) and its cut-leaved weeping variety {pcndida hiciiiiafa) 

 have suffered most from its ravages. In the outbreak in Buffalo, the 



