PEAR BORER. 6 
is probably due chiefly to the fact that the continuous working of 
generations of larvae in the bark causes a roughened surface (PL II, 
A, C) which is attractive to the ovipositing adults. Injury may 
occur at almost any point above the ground, except on the smaller 
twigs. 
Larvas are commonly found feeding in the crotches and in places where 
there is a rough or broken surface caused by the previous feeding of their 
own kind or by other agencies. (PI. II, A, C; PI. III.) Favorite 
places of attack are around the borders of mechanical wounds in the 
bark, areas affected by sun scald and winter injury, and around the 
burrows of other species of borers. The larvae often develop within 
the excrescences of stem tumor (Bacterium tumefadens) and black 
knot (PlowrigJitia morbosa), and about the borders of dead areas 
caused by pear blight (Bacillus amylovorus) . The writer has found 
pear borers attacking trees under the following conditions: In stem 
tumor of apple at Quincy, Pa., Adrian, W. Va., Demorest, Ga., 
Gadsden, Ala., and Love Station, Miss.; in black knots on cultivated 
cherry and wild cherry (Prunus virginiana) at French Creek, W. Va., and 
Winthrop, Me.; in wounds made by roundheaded apple-tree borers 
(Saperda Candida Fab.) in cultivated apple and juneberry trees 
(Amelanchier canadensis) at French Creek, W. Va., and Biltmore, 
N. C; in wounds made in cultivated apple and wild thorn trees 
(Crataegus sp.) by the spotted apple-tree borer (Saperda cretata 
Newm.) at French Creek, W. Va., and East Lansing, Mich.; in 
wounds made in apple trees by the flatheaded apple-tree borer 
(OhrysobotJiris femorata Fab.) at French Creek, W. Va.; in wounds 
made in apple bark by the yellow-bellied sapsucker (SpJiyrapicus 
varius varius) at Moorefield, W. Va., and Demorest, Ga.; and in the 
edges of wounds made in the operation of grafting apple trees at 
Lancaster and Quincy, Pa., and French Creek, W. Va. Where the 
larvae were feeding in the position last named they were interfering 
seriously with the union of stock and scion. Mr. E. B. Blakeslee, of 
the Bureau of Entomology, in notes furnished to the writer, states 
that at Winchester, Va., pear borers have been observed to complete 
the girdling of apple trunks partially encircled by collar blight. 
The damage done by a single borer is usually negligible, but the 
combined injury of a dozen or more borers may endanger the health 
or life of the tree. Often infested areas will occur at the upper part 
of the trunk where a number of branches originate (PI. II, A, C) and 
the branches will die one by one until the tree is ruined. Badly 
infested trees usually take on a scraggly, neglected appearance, the 
bark being rough and the growth slow. (PL III.) Several orchards 
were visited during the present investigation in which it was not 
unusual to find from a dozen to a hundred borers working in a single 
tree. Under such conditions treatment of some kind for saving the 
trees is necessarv. 
