INJURIOUS AND BENEFICIAL INSECTS OP CALIFORNIA 



421 



among the roots just under the surface. The pupae, when fully 

 matured, wriggle out of the burrows and protrude nearly the whole 

 length before the adults 

 escape, leaving the skins in 

 this characteristic position. 



Life History. — The winter 

 is spent in the larval stage 

 in the old burrows under the 

 hark or in small new hiber- 

 naculae in the bark made by 

 the smaller caterpillars. 

 Work is probably continued 

 throughout the winter where 

 the insect occurs in this 

 State, as all sizes of the larva? 

 may be found. When full- 

 grown the larvae leave their 

 burrows and construct co- 

 coons near the burrows or 

 roots. The pupal period 

 lasts from three to four 

 weeks, when the adults 

 emerge. These soon mate 

 and the females deposit their 

 eggs on the trunks of the 

 trees or upon the adjacent 

 weeds or ground. From two 

 hundred to eight hundred eggs are laid by a single female. These 

 hatch in eight or ten days, and the larvae make their burrows into the 

 bark of the tree through cracks or crevices. Growth is rapid during 

 the summer, so that many are practically full-grown by winter, when 

 the hibernation begins. There is but one brood a year. 



Nature of Work. — The work of this species is practically the same 

 as that of the California peach borer. 



Distribution. — Though this species has often been taken in quar- 

 antine on nursery stock, it was not known to exist in the State until 

 it was discovered at Dehesa, in San Diego County, by H. A. Weinland, 

 County Horticultural Commissioner, in the spring of 1914. Specimens 

 of larvae and pupae were received by the writer and adults reared, so 

 there is no question concerning the identity of the species. 



Food Plants. — The peach appears to be the favorite food plant. 

 though any of the stone fruits, including apricot, cherry, nectarine, 

 plum and prune, are also frequently attacked. The wild cherry and 

 wild plum and certain ornamental shrubs ate also host plants. 



Control. — The treatments are the same as for the California peach 

 borer. 



Natural Enemies. — In the Eastern Slates a small parasite (Teleno- 

 mus quaintancei Oirault) 207 destroys as many as fifty per cent of the 

 eggs. The parasite probably does not occur in California. 



Fig-. 42 9. — The peach tree borer, ZEgcria exitiosa 

 Say. Adult female at top and males at bottom. 

 Slightly enlarged Specimens reared from pupa? 

 collected in San Diego County by H. A. Weinland. 

 (Original) 



^Quaintance, A. L., rearbook, r. S. Dept. Agri 



1905. 



