THE DAVEY INSTITUTE OF TREE SURGERY 
Chrysobothris. Eight or more varieties of this species have 
been described. Among these are alabame Gory, fastidiosa 
Gory, lesueurt Gory, misella obscura Lec., 4-impressa Gory, 
semisculpta Lec. and soror. 
116. The beetles deposit their eggs during June and July, 
mostly upon the bark exposed to the sun, and at times it is a ques- 
tion whether the primary cause of the injury is due to the borers 
or to sun-scald or winter injury. However, there is no doubt but 
that healthy trees are less liable to attack than diseased trees. 
117. The food plants include oak, soft maple, mountain ash, 
box elder, hickory, chestnut, sycamore, horse chestnut, beech, wil- 
low, cultivated redbud, apple, pear, peach, plum, cherry, and cur- 
rant. 
118. Control. In orchards the best preventatives are clean 
culture and care, tending to produce vigorous growth, together 
with proper pruning to prevent exposing the trunk or large limbs 
to sun-scald. The trees should also be carefully inspected in fall 
and spring to kill any borers that may be found in trunk or large 
limbs. The use of repellents has also given good results. The 
larva do not burrow deep into the wood, so can be more easily 
located and killed than the larve of the round-headed borer. 
16. BRONZE BIRCH BORER 
Family BUPRESTID. Species Agrilus anxius Gory 
119. This flat-headed borer has killed many of the magnifi- 
cent birches in some of our northern cities, but has not been found 
to be injurious to trees under forest conditions. This is probably 
due to the effect of the birds and other natural enemies. In the 
cities, when a tree becomes infested, it seldom lasts more than two 
to three years. The species was first described in 1841. It has ap- 
peared in the literature under the names of Agrilus anxius Gory, 
Agrilus gravis Lec., and Agrilus torpidus Lec. 
120. The first indication of the destructive work of this borer 
is usually seen in the dying of some of the top branches. These 
are usually the first to become infested, and consequently the first 
to be injured. When the trees reach this stage, no remedy is 
known that will save them. The only thing to be suggested in 
po cases is the complete destruction of the affected trees, includ- 
ing all the branches down to one-quarter inch, before May Ist, to 
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