S H ADE FREE I N 8S EC tes 
the same color extending inward and backward from them. These 
teeth may or may not meet on the middle line. 
81. Control. Owing to the nature of their work and the diffi- 
culty of detecting their presence before serious injury is done, the 
elm borer is a difficult pest to control. 
82. Cut and burn all badly infected trees or parts of trees 
before May to prevent the beetles from emerging. Force the growth 
Courtesy Illinois State Entomologist. 
Fig. 8. 
Elm borer larva. After S. A. Forbes. 
of the remaining trees as much as possible. On valuable trees, 
remove all dead or badly infested bark to kill the borers under it, 
scrape off the outer bark from the rest of the trunk and larger 
limbs if infested, and spray it thoroughly with 15% kerosene emul- 
sion. If the trees are thoroughly sprayed with repellents from June 
to the middle of August, this will tend to prevent egg laying. If 
the cambium is exposed it can be protected from drying out by the 
composition described above (paragraphs 18-28). 
7. LOCUST BORER 
Family CERAMBYCID. Species Cyllene robine Forst. 
83. This-round headed borer is so destructive to black locust 
that it is difficult to grow these trees with any prospect of success 
in many localities. It has been described under the following 
names: Leptura robine Forster, Leptura picta Drury, Clytus 
flexuosus Fabr., Clytus pictus Drury, and Clytus robine Forst. 
It has also frequently been confused with the hickory borer. 
84. ‘The adult is a beautiful black and yellow beetle, quite 
similar to the maple borer. ‘These are also lovers of the bright sun- 
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