INSECT PESTS OF OHIO SHADE AND FOREST TREES 319 



Control. — Unfortunately little can be done by way of artificially 

 controlling the poplar borer. The larvae are hard to discover in 

 their winding burrows, and thus far no method has been devised to 

 prevent their entrance into the host. Cutting and destroying the 

 infested trees by June 15, at which time those badly infested are 

 most plainly marked because of the abundance of castings, would 

 in some measure curtail the spread of the pest. 



THE POPLAR AND WILLOW BORER 



(Cryptorhynehus lapathi Linn.) 



Description. — The poplar and willow borer is in the adult stage 

 a long-snouted weevil measuring from one-third to two-fifths of an 

 inch in length. (See Plate LXV, Fig. 1.) The general body color 

 is very dark gray with the exception of the tips of the wing covers 

 which are pale. The boundary line of these two-color areas is very 

 distinct as indicated by the illustration. The egg is pure white and 

 is found inserted in the corky bark of the host. The larva is foot- 

 less, grub-like, thick, and is a little less than one-half of an inch in 

 length. The pupa is about one-third of an inch long and is found 

 in a cell in the larval burrow. 



Life history and habits (49). — The winter is passed in the lar- 

 val stage. By mid-June pupation begins and the first adults make 

 their appearance after mid-July, becoming abundant in August and 

 have been observed abroad in New York as late as October 7. 

 About 10 days after emergence mating occurs and the eggs are 

 deposited. 



About 3 weeks is spent in the egg stage, and the resulting 

 larvae constitute the over-wintering form. There is but one brood 

 per season. 



Nature of work. — The injury is two-fold in nature, the punctur- 

 ing in the bark of the host by the beetles and the boring by the 

 larvae. The latter is, of course, much more important and is 

 attended with the possibilities of the fungous and bacterial infection 

 such as were described for the preceding species. 



The injury is greatest to nursery stock and newly-set trees. 

 In New York instances are on record where large quantities of stock 

 have been rendered almost worthless by this borer and at the Ohio 

 Station the pest interferes seriously with the experimental forestry 

 plots. (See Plate LXV, Fig. 2.) 



Food plants. — Doctor Matheson (49) presents the following 

 concerning food plants. "The poplar and willow borer has a fairly 

 wide range of food plants. European writers record it as attacking 

 the following species: Alders, Alnius viridis D. C, A. incana Willd., 



