112 MAINE AGRICULTURAL EXPERIMENT STATION. 



THE PEAR-BLIGHT BEETLE, OR SHOT-BORER. XylebOTUS pJU, 



Peck=:X. dispar, Fabr. 



This is a native species that attacks hemlock, beech, oak, and 

 cedar, and has transferred its depredations to apple trees in 

 Maine. We have received from several localities specimens of 

 apple limbs that were literally honeycombed with small channels 

 that extended through the laburnum and heart wood to the 

 center. The young larvae bore into the wood, making deep 

 channels which in small twigs interfere with the circulation of 

 the sap, and the twigs wither, giving the appearance of blight, 

 hence the name pear-blight beetle. The work of this beetle 

 should not, however, be confounded with the pear-blight proper, 

 which is caused by bacteria. The exit holes through the bark 

 were .06 of an inch in diameter and nearly circular, looking like 

 small shot holes. The wood was green, showing that the insect 

 attacks the growing tree. Living wood does not appear to be 

 essential to the life and comfort of this species, for after a period 

 of several weeks we found in a limb that had been in a dry place 

 in a box, young larvae, full grown larvae, pupae, and perfect 



beetles. 



Description. 



So far as we know, the eggs have not been described. They must be 

 very small and are said to be laid at the bases of the buds. We have 

 never seen them. 



When the larvae are full grown they transform to pupae in the burrows, 

 and finally emerge as small beetles about one-tenth of an inch long and 

 of a dark brown or nearly black color, with the antennae and legs of a 

 rusty red. The thorax is short, very convex, rounded and roughened. 

 The wing covers are rr.arked by longitudinal rows of punctures. The 

 hind part of the body slopes abruptly. The beetles leave their burrows in 

 July and deposit eggs before August. 



Remedies. 



As the beetles work wholly under the bark they cannot be 

 reached by insecticides. The only way is to watch the trees dur- 

 ing the latter part of June and July and, if blighted twigs or 

 diseased limbs are noticed, examine the branches for small pin 

 holes ; if found, the presence of this or some related species may 

 be suspected. The diseased limb should at once be cut far 

 enough below the injury to include all the burrows, and burned, 



