INSECT PESTS OF OHIO SHADE AND FOREST TREES 327 



Food plants. — The white birch (Betula alba) and its cut-leaved 

 weeping variety {Pendula laciniata) are the preferred hosts, and 

 the following additional species of birch have been recorded : black 

 birch (B. lenta) , yellow birch (B. lutea) and canoe birch {B. papy- 

 rifera). There is a possibility that the insect may survive in wil- 

 low and the adult beetles have been taken on cut poplars. 



Distribution. — According to Slingerland (51) writing 12 years 

 ago, "This bronze birch borer is an American insect and is widely 

 distributed throughout the northern United States and Cana(Ja. It 

 has been recorded from New Hampshire and Massachusetts, west- 

 ward through Connecticut, New Jersey, New York, Pennsylvania, 

 Virginia, Quebec and Ontario in Canada, Michigan and Illinois to 

 Colorado." 



A few years ago, probably about half a dozen, the insect entered 

 Ohio at Toledo from Michigan, and is gradually working southward. 

 This fact together with that that the insect is known to be well 

 established in Buffalo and western New York to the east indicates 

 that it is only a matter of time until the State, and particularly the 

 northern part will be generally infested. 



Natural enemies. — Woodpeckers are known to be of great value 

 in searching out and destroying the bronzed birch borer before the 

 insect escapes from the tree. Slingerland (51) reports breeding 

 out a parasitic Chalcid fly, Phasgonoj)hora sulcata Westwood, from 

 this pest and since the parasite is widely distributed it would seem 

 that it may be of considerable natural value in controlling the 

 species. 



Control. — No method is known by which a tree may be pro- 

 tected in the presence of the adults of the bronze birch borer. The 

 only suggestions we are able to make at this time by way of mini- 

 mizing the injury, is the practice of sanitation with the thought of 

 reducing the numbers of egg-laying beetles. All trees known to be 

 infested with the bronze birch borer should be cut and burned before 

 the last of April to prevent the emergence of the adults. The cut- 

 ting out of the dead top of an affected tree is a mistake, for not only 

 is the uncut remainder of no value from the esthetic standpoint, but 

 when the infestation is sufficiently severe to cause the death of the 

 top, the remainder of the tree usually will be so badly infested that 

 it will merely serve as a breeding place of infection. 



THE MAPLE AND OAK TWIG PEUNER 



(Elaphidion villosum Fabr.) 



Description. — Perhaps as much mystery surrounds the activi- 

 of this twig pruning insect as any other shade tree or forest pest. 



