108 MASS. EXPERIMENT STATION BULLETIN 160. 



into extensive use with other insects long ago. Sweetened poison baits 

 have long been widely used against grasshoppers and cutworms, and 

 molasses is commonly used by entomologists to attract many kinds of 

 moths in night collecting. Sweets are, therefore, evidently liked by 

 many insects, and the idea of sweetening arsenical sprays seems worth 

 trying out thoroughly on that account. The fireworm's hatching period, 

 however, often covers several weeks, and, in order to be satisfactorily 

 effective, any poison apphcation must remain on the vines in consid- 

 erable strength for quite a long time. Sweets being very soluble in water, 

 if used in a spray, will not remain on the vines long if much rain falls. 

 There are, therefore, considerable difficulties to be overcome in making 

 satisfactory use of a sweetened spray. 



The outlook, therefore, does not seem bright for treating this insect 

 more satisfactorily by direct methods. It may be possible, however, to 

 treat it indirectly in some Avay. As stated in previous reports, it does not 

 seriously infest bogs without winter flowage. If infested bogs could be 

 left entirely without flowage, the insect would in time probably be con- 

 trolled by weather conditions and its natural enemies. If bogs are not 

 winter flowed, however, other troubles have to be met. In the first place, 

 there is the danger of winterkilling, though this factor is not as important 

 as is generally supposed, for severe winter injury does not occur on dry 

 bogs oftener than once in four or five j'ears, and even then the bogs are 

 seldom so hurt that they do not produce partial crops and recover in 

 fair shape for the following year. The fruit worm increase which takes 

 place when winter flowage is omitted is, however, a serious matter, and 

 a satisfactory treatment for that insect is, for that reason, a possible key 

 to the fireworm situation. If the fruit worm could be controlled without 

 winter flooding, the forces of nature could be brought to bear in the fight 

 with the fireworm by omitting flowage altogether. 



The Cranberry Fruit Worm {Mineola raccinii (Riley)). 



Late holding of the winter flowage continues to be the only certainly 

 reliable method of dealing at all satisfactorily with this insect. A better 

 treatment is desired because the water does injury when held late every 

 j^ear. Any new treatment of value must probably be an indirect one. 



As stated in last year's report (page 57), tests showed that the cocoons 

 of the fruit worm are not impervious to water, for they were found to be 

 wet inside when carefully opened after only a few minutes' submergence, 

 the water apparently having penetrated them almost instantly. This 

 was further tested later by wetting dry cocoons with a spray from a 

 Vermorel nozzle, and the water seemed to strike through them as readily 

 as it would have through a handkerchief. It seemed from this that it 

 might be possible to kill the worms in their cocoons on the bog bj^ spray- 

 ing with some contact poison, as the spray would evidently soak through 

 the cocoons at once. The writer conducted laboratory experiments 

 with "Scalecide" and "Black Leaf 40" to determine what strength of 



