MONTANA EXPERIMENT STATION. 



155 



ROUND-HEADED APPLE-TREE BORER. 



The round-headed apple-tree borer is much less frequently met 

 with than the "flat-headed" speci&s but its injury is more serious. Af- 

 fected trees assume a sickly appearance and fail to make the proper 

 growth. On the trunks may often be seen masses of the castings 

 at the openings to the burrows. In some parts of the country 

 this has been a very serious enemy to apple trees. 



Besides attacking the apple it is found in various other woody 

 plants including crabapple, quince and pear, l^xperience has shown 

 that trees are very much more liable to be attacked if the trunks are 

 surrounded by grasses, weeds or other vegetation. 



The adults appear in the spring of the year and the females de- 

 posit their eggs as near to the ground as possible. The eggs hatch 

 in about three weeks and the larvae work their way under the bark 

 and feed for the first season in the sapwood. During the second sea- 

 son they feed in the deeper heartwood and in the third spring bore to 

 near the surface where they transform to pupae the adult beetles ap- 

 pearing a little later. The adult is a beautiful insect measuring 

 three fourths of an inch to an inch in length. The under surface 

 of the body is silvery white while the upper surface is brown with 

 two longitudinal white stripes. 



This insect may be introduced into Montana in nursery stock. 

 In looking for it the bases of the trunks should be closely examined. 



Fig. 4. Round-headed Apple-tree Borer: a. larva, from side; b, from above; 

 c, female beetle; d, pupa; all enlarged one-third. (Marlatt, Circular 32, Sec. 

 Swies, Div. of Entomology, U. S. Dept. Agr.) 



