12 BULLETIN 261, U. S, DEPARTMENT OF AGRICULTURE. 
NATURAL ENEMIES. 
The larvae of Euzophera semifuneralis are attacked by a number 
of parasitic and predaceous enemies. Two parasitic forms were 
reared at Winchester in 1913, which were determined by Mr. E. A. 
Cushman, of the Bureau of Entomology, to be IdechtMs sp. (PI. Ill, 
a) (Quaint ance No. 10402) and Mesostenus thoracicus (Cress.). 
The former was by far the more common. Of 104 overwintering 
larvae collected in the field 14 were parasitized by this insect. This 
proportion of parasitized specimens, amounting to 13.47 per cent, 
indicates that the parasite may aid very materially in the control 
of the borer. The parasitized larvae are about one-half normal size 
and usually lack the greenish-brown color of healthy specimens. At 
some time during the prepupal period the parasite matures, devours 
the larva, and spins its cocoon (PL III, c). Fred Johnson, in 1905, 
at Youngstown, N. Y., reared an undetermined member of the family 
Ichneumonidae (Quaintance No. 574). J. H. Beattie, hi 1905, at Fort 
Valley, Ga., reared from borer larvae Itoplectis marginatus (Prov.), 
Mesostenus gracilis Cress., and Pimpla sp. (Quaintance No. 399). 
Mr. FredE. Brooks, of the Bureau of Entomology, records rearing a 
hairworm, probably a species of Mermis (PL III, h), from larvae of 
the plum borer. 
Among the predaceous enemies the larva of Tenebroides corticdlis 
Melsh. has been taken feeding upon the borer. Ants and wood- 
peckers are also important factors in reducing the numbers of this 
insect. 
REMEDIAL MEASURES. 
As has already been stated, the plum borer will probably never 
become a pest of more than ordinary importance, except in occa- 
sional isolated cases. Its food habits are such that it is entirely 
unable to establish itself upon vigorous, healthy, uninjured trees. 
However, in common with a number of other insects it does deserve 
some attention on account of its ability to do considerable real injury 
where the proper conditions are presented, i. e., where trees have 
been injured by hail, frost, or attacks of fungous diseases, and its 
rather indiscriminate choice of food plants increases its opportunities 
in this direction. One of the most common instances of this in the 
observation of the writer is in the case of the collar blight of apple, 
where the injury done by this disease is frequently supplemented by 
subsequent attacks of the plum borer. When the ordinary precau- 
tion of cutting away the dead bark and painting the wounded areas 
is followed, this may be regarded as sufficient for the control of the 
borer. Where the borer has established itself already the cutting-out 
method is the only one that can be followed. Nothing may be 
expected from the application of poisonous washes. 
