Green Cranberry Spanworm ^^ 



This species occurs in limited numbers on most Cape Cod bogs and does con' 

 siderable harm nearly every year. It broke out on many bogs in 1920 and 1921, 

 destroying the entire crop promise on a large acreage. Growers of long ex' 

 perience said it had been similarly prevalent for a time some twenty years before. 



Distribution and Food Plants 

 This moth ranges from Nova Scotia to British Columbia and has been found 

 in Massachusetts, New York, New Jersey, and Wisconsin. No food plant besides 

 cranberry is known. 



Character of Injury 

 When the winter flowage is held till mid' or late May, some of the worms 

 hatch in time to eat into terminal buds like false armyworms (fig. 22). They 

 seldom do much harm in this way. They usually work hke the blossom worm, 

 nipping off flower buds and blossoms by severing the stem near where it joins 

 the ovary (fig. 28). When extremely abundant they attack the leaves and 

 sometimes brown a small area. 



Description and Seasonal History 



THE EGG 



There is one brood a year. In late June, July, and early August the female 

 moths scatter their eggs singly among the litter under the vines, laying about 

 125 each. They usually stick to fallen leaves or pieces of dead twigs (fig. 29). 

 They are greenish white, elliptical, and about a thirtyseventh of an inch long. 

 They are surprisingly rigid and unyielding as they come from the moth's body 

 and, when examined with a microscope, are seen to be thickly studded, ex' 

 cept more or less on a central area above and below, with minute round smooth 

 white tubercles (fig. 30). They often become somewhat sunken in the middle as 

 hatching approaches. The winter flood does not harm them even when held late. 

 When it is let off in April, hatching begins from about May 1? to about June 1, 

 depending on the advancement of the season, and may continue till about July 1. 



GREEN CRANBERRY SPANWORM 

 Fi(i. 30. One egg. Greatly enlarged. 



THE WORM 



During most of their life the worms (Plate Three, figs. 3 and 4a) are green 

 with several white lines along the back and sides and a narrow light yellow 

 stripe along each side. In their last stage (Plate Three, fig. 4b) the green has 

 a yellow tinge and the whitish lines are obscure except for a pair along each 

 side of the back which often are more marked. They mature from about June 

 10 to about July 22, becoming an inch long. 



^ I tame siilphurca (Pack.). 



[38] 



