12 MASS. EXPERIMENT STATION BULLETIN 239 



Because of ics partial suppre.ssion, tliis brood usually is well bundled in hatch- 

 ing; (2) the worms are killed most easily wiien small; (3) if treatment is 

 delayed, the worms may injure the tips so that they will not bud well for the 

 next year; and (^j the worms that enter berries cannot be reached with a 

 spray. 



A half-effective spraying with nicotine sulfate for a moderate infestation 

 sometimes may do almost as much harm as good, for it affects the worms 

 less tlian tiieir nuicii more exposed natural enemies. 



Outbreaks of a disease'- sometimes wipe out the second iirood on many liogs. 

 If spraying is contemplaied or in progress, it is well to watcii for tius, for 

 the epidemic uiay make treatment imnecessary. Tiie general abundance of the 

 fungus tluit causes it may be learned by leaving fifty of the worms in a moist 

 chamber'^ over night. By morning it will appear on most of the diseased ones 

 as a fluffy white mold, and around them as a ring of white sj)ore dust. Prof. 

 W. H. Sawyer, .Jr., has found this fungus absent or inactive on the bogs with 

 fireworm infestations notably resistant to control but generally abundant on 

 otlier infested areas. He has found further tliat tlie bogs on which it is scarce 

 are generally large, well-managed areas that have l)een flooded, sprayed and 

 resanded regularly. Evidently it is killed out, directly or indirectly, by late- 

 spring or summer flooding or by spraying or sanding, for no evidence has been 

 found that fall flooding or the winter flood, even wlien it is held late, affects 

 it. If, as the writer suspects, the early-summer flooding is responsible, this 

 sliould not he preferred to spraying as a treatment for insects except possibly 

 on bogs with false blossom. The fungus passes the winter in the form of 

 resistant spores among the chaff on the bog floor. 



Moderate infestations of this fireworm must be treated as though tliey were 

 severe. Even sliglit ones should be given due attention, especially on large 

 bogs. They should be treated at least once during the season. 



Yellow-head'cd Fireworm." 



This pest never harms bogs that are flooded completely during the winter 

 on Cape Cod and seldom does elsewhere, for the wintering moths cannot en- 

 dure submergence. It is attacked by parasites much more than the black- 

 lieaded fireworm. They do not reduce the first brood much, but they decimate 

 the second so that, however severe the infestation, the first brood of the next 

 year never does much harm. There are two broods in Massachusetts, three in 

 Iowa and Wisconsin, and three and sometimes four in New Jersey. 



Dlnfribution and Fond Phnifn. 



This fireworm is known widely as an apple pest throughout the L'nited 

 States and soutliern Canada. It also feeds on huckleberry, swamp blueberry,'^ 



12. Caused by EnUimuphihora sphaerosperwa Fres. This fungus also attacks other insect 

 species. Prof. Sawyer has grown it abundantly on various culture media. This seems to have 

 been the first really successful culturing of a fungus of this genus. Prof. Sawyer is doing his field 

 work on this disease in co-operation with the Cranberry Station at East Wareham and studying 

 it ftirther in the Laboratories of Cryptogamic Botany at Harvard University. He is examining 

 carefully the possibilities of controlling this fireworm by distributing the culture-grown fungus 

 in a spray or otherwise. 



13. A clear smooth tumbler inverted over a glass plate and containing a little moist cotton 

 is handy for this. 



14. Peronea miniUa (Rob.). 

 1.5. Vaccinium cnrymbosum L. 



