BlacK'Headed Fireworm 5 



If we consider all the cranberry growing sections of the country, this is the most 

 harmful cranberry insect; and in Massachusetts only the fruitworm and the root grub 

 (Amphicoma) do more damage. Means of control, however, have now dc 

 veloped so that much injury by it suggests poor management. 



On Cape Cod, this insect rarely harms seriously a bog that has not been flooded 

 during the winter, and its infestations cling more tenaciously to large compact 

 bogs than to small areas. The water kills or drives ashore its enemies, such as 

 spiders and parasites, and protects its eggs from winter adversities. The foes of 

 the pest are, of course, slower in again reaching the center of a large compact 

 bog in effective numbers than they are in reaching that of a small one. So an 

 infestation developing on a large bog always gets serious on the middle part 

 first. 



Distribution and Food Plants 



This fireworm is very destructive in Nova Scotia, Massachusetts, New Jersey, 

 and Wisconsin and on Long Island and the coast of Oregon and Washington. ^ 

 It has been found in Maine and California. It is not known to feed on anything but 

 cranberry.'^ It generally attacks Howes and Smalley Howes vines more than 

 Early Black. 



Character of Injury 



The newly hatched worm of the first brood usually begins by burrowing into 

 the under side of an old leaf, the new growth of the season not yet having put 

 out, and works as a leaf miner, casting out on the lower surface a small mass of 

 refuse (fig. 1). An area on the upper side immediately over these castings is 

 lighter colored than the rest of the leaf, and the first hatching of the insect often 

 may be detected most easily by these light patches. 



If the hatching begins early, the young worms, on leaving their mines in the old 

 leaves, mine the terminal buds just as they are swelling to start new growth, and 

 sometimes ruin most of them before being discovered. 



As new shoots appear, the worms proceed to sew three or four of their tip 

 leaves together. If the worms hatch after the new growth develops, they usually 

 go directly to the new tips without mining the old leaves. The webbed tips 

 generally are the first work noticed by growers (fig. 2). 



The worm usually leaves the tip it has sewed up within a few days and either 

 webs leaves farther down on the shoot or goes to another upright the new growth 

 of which it sews up, commonly webbing in one or more other uprights. If the 

 worms are very abundant, two or three often work together and include several 

 uprights in their nest (fig. 3). They feed freely on the new leaves and flower 

 buds in their nests, often destroying the whole crop prospect and turning the 

 bog brown. 



During the interval between the two broods, the vines put forth more new 

 growth and recover considerably from their injury. 



° Rhopohota vacciniana (Pack.). The writer is not convinced that this species is the 

 same as the European hollv feeder, R. nacvana (iHubnev), and hesitates to follow Heinrich 

 (U. S. Dept. Agr. Bui. l532, p. 45, 1922) and McDunnough (Memoirs, So. Calif. Acad. 

 Sci. Vol. 2, p. 50, 1939) in this. 



' Only on the Pacific coast does this fireworm thrive generally on bogs not flooded during 

 winter. It probably was not present there till it was introduced from the East (U. S. Dept. 

 Agr. Bui. 1032, p. 4, 1922). See also copy of letter of Charles D. McEarlin to E. R. 

 Peterson, 9/22/1906, in Middleboro library. 



^ Vaccinium macrocarpon Ait. and V. Oxycoccus L. 



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