

INJURIOUS AND BENEFICIAL INSECTS OF CALIFORNIA. 



THE PEACH TWIG-BORER 



Anarsia lineatella Zeller (Family 



Gelechiidae) 



(Anarsia pruinella Clemens) 



(Figs. 45 0-453) 



Description. — The adults of this 

 insect are seldom if ever observed by 

 the average orchardist. They are 

 small, between j and | inch long, and 

 dark silvery-gray in color. The pres- 

 ence of the larva? is easily told in the 

 spring by the dying back of the young 

 buds and twigs. The larvae arc small, 

 scarcely more than | inch long when 

 full-grown. The color varies from 

 pink or dusky-white to dark brown, or 

 almost black. The cocoons are dark 

 brown and are hid away in small pro- 

 tected places. 



Life History. — The larvae hiber- 

 nate in small chambers or hibernaculae 

 made just beneath the bark in the 

 crotches, being found most commonly 

 where branches are from ^ inch to 2 

 inches in diameter. They may be 

 located by the small chimneys of frass 

 pushed out in the process of making 

 (Figs. 450, 351). In the spring, just 

 before or at the time when the leaf 

 buds begin to open, the larvae leave 

 their places of concealment and seek 

 the young buds for food. They begin 

 to work near the tips in the leaf axils 

 and bore down the center of the stem, 

 killing the tips. By May most have 

 become full-grown. They seek crev- 

 ices or any suitable place of conceal- 

 ment, and after spinning a frail web 

 over the entrance (Fig. 452) trans- 

 form into pupa 3 , and within one or 

 two weeks emerge as adults. Not all 

 of the larva? are full-grown by May, 

 and the later individuals attack the 

 fruit just as it is beginning to mature 

 in June. It has been thought that the 

 larvae attacking the fruit were of the 

 second generation and that there was 

 still a third brood, but observations 

 made throughout the state by Geo. P. 

 Weldon and in the Sacramento Valley by the writer seem to show that 

 such is not the case. In fact, the study made by Mi-. Weldon on the 



Fie*. 4,Tn. — Hlbi or winter 



chambers of the larvae of the peach 

 twig-borer, Anarsia lineatella Zeller. 

 Enlarged six times. (Original) 



