Thk Raspberry-Cane Maggot. 55 



Indications of the Presence of the Insect. 



This raspberry-cane maggot attacks only the new shoots which 

 appear in the spring. The results of its work are very conspicu- 

 ous, and raspberry growers can thus easily determine if the insect 

 is present in their fields. Three injured shoots are represented, 

 natural size, in figures 20 and 21. These figures show that the tips 

 of new shoots attacked by the insect wilt and droop ; the stem of 

 this tip shrinks, turns dark blue in color and finally dies. The 

 wilted tip may be easily broken off at a certain point. If the 

 shoot be carefully examined at this point it will be found to haye 

 been girdled by the insect from the inside ; how this girdling is 

 done will be described in telling the life-history of this pest. 

 Sometimes a very vigorous shoot will continue its growth from 

 side buds, thus forming a branched cane, but usually the injury to 

 the tip results in the death of the whole shoot. In one case the 

 terminal tip and the tips of three of its side shoots had all been 

 killed .by the insect. 



The pest begins its destructive work as soon as the shoots ap- 

 pear above the ground in the latter part of April, and its work 

 continues during the whole of May. All sizes of the new shoots 

 are attacked ; those in figures 20 and 21, and at b, plate V, are 

 represented natural size. 



Thus when raspberry growers find the tips of new shoots wilted 

 and drooping in May, it is an indication that this new insect pest 

 is at work in their fields.* 



The Appearance of the Insect. 

 Although raspberry growers will have no trouble in discovering 

 the work of this pest, only the most careful observers will doubt- 

 less ever see the adult insect. So close is the resemblance, that 

 the ordinary observer would say that the little flies, which may 

 be seen on the new shoots in May, were simply house-flies. But 

 a careful study of one of the flies, shown much enlarged at a 



*The raspberry-cane borer ( Oberea bimaculata, causes the tips of the glow- 

 ing canes to wilt and droop in a similar manner, but this insect does not be- 

 gin work until considerably later, in June. Thus the work of the two 

 insects need not be confounded in our state. 



