260 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 14 



when grain is standing in stocks. Some kinds of twine, as for instance thrt which 

 is loosely twisted, has been more attractive to insects. We have used several 

 mixtures to protect the twine from locust injury and the following has been found 

 most useful. 



Bluestone . . 1 pound 



Water . . . ' 6 gallons. 



The balls of binder twine should be soaked in the solution for half an hour, and then 

 dried thoroughly before using. The mixture, of course, is not intended to destroy 

 locusts: it simply acts as a deterrant." 



Washburn. Minn. Agric. Expt. Station. 1903. Press Bulletin No. 16, page 6. 



"To prevent crickets and grasshoppers from eating binder twine in the fields: 

 Soak balls of twine in a solution of 2 lbs. bluestone dissolved in 12 gallons of water, 

 for half an hour and then dry it thoroughly. (H. Vane, in Canadian Report.) 



It must be remembered that it is hard to dissolve bluestone; it should therefore 

 be placed in the water quite a long time before the liquid is to be used. 



A farmer here suggests soaking balls of twine in kerosene. This might be effec- 

 tive." 



Being unable to locate the vague reference to Mr. H. Vane, the fol- 

 lowing explanation is offered through the courtesy of Mr. Criddle in a 

 letter of recent date. 



"The experiments conducted by Mr. H. Vane were undertaken with a view to 

 protecting the binder twine from the ravages of locusts. Several substances were 

 tested, including coal oil and salt, but the only one giving immunity was from soak- 

 ing the balls of twine in a solution of Bluestone (Copper sulphate) and water. 



I may say that the Bluestone solution was used by many of us and proved very 

 satisfactory excepting for the fact that it had a tendency to weaken the twine. We 

 found also, that it tended to clog in the binder but that it worked much better when 

 thoroughly dried. 



Mr. Vane is a farmer of these parts and has not published any information on 

 the above subject." 



During the past season , in order to obtain further information on this 

 this subject, a series of experiments was conducted in which one to 

 two hundred sheaves were bound in the usual manner, with each of 

 the several variously treated twines and exposed naturally in the field. 

 A similar test was run in each of six widely separated localities from 

 which trouble of this sort had been reported the previous season. Just 

 before threshing, an examination was made for cut bands and not a 

 single band was found cut in any locality, even of the untreated twine 

 used as a check. 



It was then decided to carry out some elimination experiments by 

 some other method to determine if possible which of the ordinary re- 

 pellents would probably be best for actual field application. The 

 method of determining the relative value of the various repellents used 

 was the same as described by Larrimer and Ford in a previous paper 



