CAPE COD CHANBERRY INSECTS 21 



CUTWORMS. 



These worms feed openly, never webbing tlie vines. They are one and a 

 half to two inches long when mature, and without noticeable iiair. They feed 

 mostly at night, usually hiding during the day among the vines or in tlie litter 

 on the bog floor or under pieces of board if such are present. They all belong 

 to the same family and, except for differences in coloration, are nuich like 

 garden cutworms. Most of them are conunon pests of other crops. All but 

 the false armyworm do injury out of all proportion to the amount of their 

 eating by cutting off flower buds, flowers, small berries or leaves and dropping 

 them to the ground. The green leaves fallen on the water in the hog ditches 

 are often the first sign of their work observed. The moths of all but the 

 blossom worm ordinarily are night-fliers and seldom seen. They measure an 

 inch and a half or more across their outspread wings. Their eggs (fig. 23) 

 are round, slightly flattened, and marked with many ridges radiating from 

 the summit. The worms generally are severely parasitized. 



These insects, except the false armyworm and the blossom worm, rarely 

 attack cranberry bogs mucli unless the winter flowage has been held until the 

 last of May or later^\ This may be due to one or botli of the two following 

 possible causes, the first lieing the more likely''-: 



1. The moths seem to prefer to lay their eggs on or over damp earth. Bogs 

 drained during the flight of the moths therefore probably invite infestation. 



2. By breeding on freshly drained areas the insects may escape their na- 

 tural foes largely and so develop as they could not otherwise. 



The chances are two to one that some of these worms will infest a bog if 

 the winter flood is held till June. Sometimes two species attack a bog to- 

 gether under such conditions and occasionally one is prevalent on some bogs 

 and another on others. They usually appear about two weeks after the water 

 is let off. 



The various s])ecies are hard to distinguish for a time after they hatch, all 

 being then mostly whitish or greenish, but they may be identified after they 

 are half-grown by the following: 



Table of ^Vort)ls. 



Mostly dark, without definite side stripes black cutworm (p. 31). 



With a conspicuous stripe along each side 1 



1. With a row of two to four angular dark spots on each side 



of the hind part of the back spotted cutworm (p. 28). 



Without such spots 2 



2. The back reddish lirown and not marked with pale yellow dots 



cranberry blossom worm (p. 26). 

 The back mostly dark, grayish, or green 3 



3. Found on a bog bared of its winter water before May 20 



false armyworm (p. 23). 



Found on a bog liared of its winter water after May 20 i 



k With many small round or o\aI dark tubercles noticeable 



along the back fall armyworm (p. 35). 



The back without such tubercles; each leg of the four pairs 

 ]ilaced together near and beliind the middle of the body 

 striped noticeably across the middle of the outer side with 

 deep brown armyworm (p. 32). 



.31. Refloodins for ten days or longer in late May sometimes has the same effect that very 

 late hoi ding of the winter water has. If the winter water is let off and the bog is flooded again 

 within a. few days, the reflood should be regarded as a continuation of the winter flood as far as 

 its relations to these cutworms are concerned. 



32. Mass. .\gr. Expt. Sta. Bui. 192. p. 133. 1919. 



