THE CEANBEBRY GIRDLER. 3 



p. 40, fig. 1) gives sheep sorrel as a host. In later years cranberry 

 is mentioned frequently. On cranberry the larvae confine their feeding 

 to the woody parts, such as the runners and the larger roots, and occa- 

 sionally some of the finer roots are taken. 



The investigation in New Jersey shows that a sedge, commonly 

 called "three square" (Scirpus americanus) , is fed upon liberally 

 when present in cranberry bogs. This is one of the abundant bog 

 weeds, and the larvse attack it at the crown, sometimes forming their 

 cocoons in this situation. 



FEEDING HABITS AND DESTRUCTIVENESS. 



All the injury is done during the larva stage, beginning in early 

 June and continuing throughout the summer and fall until about 

 mid-October. The worms are slow of growth, and the dying of the 

 vines can not be detected readily until late August or September. 

 During the early part of the season the worms are small and feeding 

 is not extensive, but in late summer, when the worms are nearly full 

 grown, they are ravenous feeders, and the lessened vitality of the 

 vines is evidenced by the appearance of the foliage, which becomes 

 fiery red or brown in September and October. Large quantities of 

 the leaves drop off, and the few which remain on completely girdled 

 vines become dry and drop during the winter, leaving areas of dead 

 vines denuded of foliage presented to the view the following summer. 

 Such dead areas may vary in size from a square foot to spots con- 

 taining many square rods. At the close of a second year of infesta- 

 tion many of these dead areas will become merged, owing to the dying 

 out of the vines in the intervening areas, by further girdler feeding. 

 Under such conditions it is common to find areas of dead vines, 

 leafless and very conspicuous by their black color, comprising as 

 much as one-half acre (PI. I). Usually the vines around the mar- 

 gins of the dead areas die back a little farther each succeeding year, 

 although if the work of the girdler ceases, runners may spread out 

 over the dead vines and tend to re-cover the area. This, however, is 

 a very slow process, involving several years, and in the meantime the 

 spot very frequently becomes a verdant patch of grass or sedge. In 

 certain bogs small areas 2 or 3 feet in diameter (PI. II, A) may be 

 killed, particularly where the trash is very thick beneath the vines, 

 as is likely to be the case in some of the corners, and the damage will 

 not grow to alarming proportions. Such areas vary little in appear- 

 ance from year to year until at some time the girdlers are exter- 

 minated, perhaps by a prolonged flooding of the bog. Then the run- 

 ners push out and eventually fill in the bare spaces. 



Where girdler feeding has not been severe enough completely to 

 kill the vines, and even in those places where only slight gnawing 



