226 MASS. EXPERIMENT STATION BULLETIN ISO. 



The Cranbemj Tip Worm {Dasyneura vaccinii Smiths). 



The season's observations of the effect of resanding on the abundaDce 

 of this pest sustained the conchisions heretofore reported. 



One species of Chalcidicl {Tetrastichus sp. ^) and two of Proctotrypid 

 {A'phanogmtis sp. ^ and Ceraphron sp. ') parasites were reared from the 

 larva; of the last brood after they had encased themselves in their cocoons 

 this season. Two of these {Tetrastichus sp. and Aphanogmus sp.) emerged in 

 only small numbers, but the Ceraphron species had infested a large, though 

 undetermined, majority of the maggots collected by the writer, and its 

 adults kept coming out from August 9 to September 14, inclusive, their 

 period of most rapid emergence being from August 12 to August 22. 



The eggs of the tip worm are not "white" as they have been described.* 

 They are watery translucent in appearance, with scattered pinkish pig- 

 ment, and are about one-third of a millimeter long. They are elongate, 

 usually slightly curved from end to end, with rounded and slightly nar- 

 rowed ends and without noticeable surface markings. 



The Black-Head Fireworm {Rhopobota vacciniana (Pack.)). 



Prof. H. B. Scammell, in cranberry insect investigations in New Jersey 

 for the Bureau of Entomology, had much success last year in treating 

 both broods of this insect in the worm stage with a form of nicotine sulfate 

 known as "Black-Leaf 40." He used 1 part of this insecticide to 400 parts 

 water, and added resin fish-oil soap at the rate of 2 pounds to 50 gallons 

 to make the spray spread and stick. When the writer saw the plots 

 Professor Scammell had treated in this way, they were green and had a 

 fair amount of fruit, whereas the surrounding bog, and even plots sprayed 

 with arsenate of lead, had been turned brown by the insect and bore prac- 

 tically no crop. 



The writer tried this treatment against the first brood on two large 

 plots this season, and while it failed to control the insect entirely, it 

 checked it so much that the plots remained green while the surrounding 

 bog was turned rather brown, the contrast being striking. 



This insecticide must be tested further before it can be said at what 

 strength it should be used or how many times it should be applied to either 

 brood. At the strength in which it has so far been tested it is a rather 

 expensive treatment, costing about $7 per acre per application. It may be 

 found, however, that weaker mixtures suffice. At any rate, this treatment 

 stands at present as the only really effective method of controlling the 

 first brood of this insect, burning and flooding excepted, and in spite of its 

 expense it will, therefore, find favor in the management of many bogs. 

 Two, and perhaps three, applications for the first brood are advisable. 



> Bui. No. 175 of the New York State Museum, p. 151. 



2 Determined by Mr. A. A. Girault of the Bureau of Entomology. 



3 Determined by Mr. J. C. Crawford of the Bureau of Entomology. 



* Smith, J. B.: Insects Injurious in Cranberry Culture, Farmers' Bulletin No. 178, U. S. Dept. 

 Agr., 1903, p. 19. 



