Nature of Weevil Feeding and Damage 



Weevil damage is in the nature of defoliation caused by adults feeding on the 

 needles of the current year's shoots. In preparing to feed, adults position themselves 

 longitudinally on the needle (fig. 3) usually facing the tip. As feeding begins, the 

 needle epidermis is first punctured by the mandibles, then feeding continues on into 

 the palisade layer and other needle tissues. At times, a weevil will abandon a feeding 

 site at this point and move elsewhere to begin a new feeding puncture. When this hap- 

 pens, the needle is not completely punctured. At other times, the weevil feeds at a 

 given point until a hole is punctured clear through the needle (fig. 4). 



Shortly after the punctures are made, those portions of the needles outward from 

 the feeding site desiccate and discolor, providing the puncture went deep enough into 

 the needle (fig. 5). Dried-up portions of the needles are blown away by wind, or 

 broken off by rain or snow, leaving only a needle stub proximal to the feeding 

 puncture. Occasionally, damaged portions of needles persist through the following 

 spring and summer. 



If feeding is only superficial, the portion of the needle beyond the puncture re- 

 mains green and persists. The second needle from the left in figure 5 shows such a 

 superficial feeding puncture. When a deep puncture is made through the needle sheath, 

 both needles are usually damaged and the entire fascicle is lost. Weevils do not 

 restrict their feeding to any particular area along the length of the needle. 



5 



