PKOGKESS REGARDING SUGAR-BEET WEBWORM. 



65 



alkali and other impurities which tend to make soluble some of the 

 arsenic and copper in the Paris green. The soluble arsenic burns the 

 beet foliage, and on account of this injury refuse molasses is not 

 recommended. It may be interesting to add that in experiments 

 which the writer made with Paris green against other species of in- 

 sects, using as an adhesive refuse molasses from cane mills, which was 

 less highly charged with impurities, the results were satisfactory, 

 and no burning of the sprayed foliage occurred. 



Several standard brands of arsenate of lead have been tested 

 against the sugar-beet webworm in the Arkansas Valley, and with- 



Fig. 16. — Barrel sprayer in action against the sugar-beet webworm. (Original.) 



out exception the results have proven unsatisfactory. The arsenate 

 was used at the rate of 6, 8, and 10 pounds in 100 gallons of water, 

 and 100 gallons per acre applied, but the webworm was not con- 

 trolled. In these experiments a large traction sprayer and an ordi- 

 nary barrel sprayer were used. 



Zinc arsenite, when used at the rate of 4 pounds in 100 gallons of 

 water and applied at the rate of 125 gallons per acre, was effective. 

 It was, however, noticeably slower in its killing effects than Paris 

 green as recommended in formulas Nos. 1 and 2, and when used at 

 this strength was equally as expensive as an effective application of 

 Paris green. 



