334 FRUIT INISECTS 



The Raspberry Horntail 

 Hartigia ahdominalis Cresson 



In California the tender tips of the young shoots of the rasp- 

 berry, blackberry, loganberry and rose are often girdled and 

 killed by the spiral burrows of the young larvae of a small 

 yellow and black horntail fly. The adults are slender, four- 

 winged flies about | of an inch in length. They appear on 

 the berry bushes the last of April and remain abundant until 

 in August. The female inserts her smooth, pearly-white, 

 flattened oval eggs, about yV inch in length, singly just under 

 the bark of the young canes. The newly-hatched, yellowish- 

 brown larvae feed for a time in the vicinity of the egg, and 

 when about J of an inch in length burrow spirally downward 

 three or four times around the cane, working just beneath the 

 bark and thus girdling the tip. The larva then enters the pith 

 and burrows upward until the tip of the branch dies, when it 

 turns round in its burrow and works down through the pith, 

 towards the base of the cane. The larvae become full-grown 

 in from four to six months and are then nearly an inch in length 

 and nearly white in color. They pupate at the end of the bur- 

 row and the adults gnaw their way out of the cane. There are 

 said to be several broods annually. 



The location of the egg may be easily determined by the 

 discoloration of the surrounding tissue, and it may easily be 

 crushed by hand. This is probably the most feasible method 

 of controlling the pest. Many of the larvae might also be 

 destroyed by cutting off the dying tips of the canes as soon as 

 wilting of the leaves is observed. This work cannot be done in 

 the winter as it is then difficult to distinguish the infested canes. 



Reference 

 Monthly Bull. St. Com. Hort. Cal., I, No. 12, pp. 889-901. 1912. 



