114 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 1 



the army engineers in destroying the water hyacinth in the bayous 

 and navigable streams of the southern states. The cost of the ingre- 

 dients, and particularly of the arsenic, showed that the use of this 

 preparation, even though it might meet all requirements, would in- 

 volve an outlay too great to make its use profitable in the cotton fields. 



It was also thought that the cotton plants might be killed by ' ' gird- 

 ling" the base of each with a flame from a gasoline blow torch, and 

 this was accordingly tried. "With cambium layer and bark entirely 

 burned off, the plants died immediately and the green bolls after- 

 wards opened fairly satisfactorily. However, a much more severe 

 burning was necessary to kill the plant than was anticipated, from 

 five to ten minutes' application of the flame to the base of each plant 

 being necessary to insure death. On account of the labor involved 

 this method was put aside as impracticable. 



Spraying solutions were next tested, most of the experiments being 

 made during the month of September. Several healthy plants were 

 sprayed by hand with each solution tested, with the general results 

 indicated below. 



A 5% solution of common salt burned the foliage rather severely 

 and caused some of it to shed, but the plant continued to grow and 

 put on foliage and squares. The application of the salt solution to 

 the larger unopened bolls caused them to open suddenly, without the 

 lint maturing properly. 



A 5% solution of bicarbonate of soda produced little effect, except 

 that some leaves and squares were wilted. In six days after spray- 

 ing the plants had practically recovered and were growing rapidly. 



A 5% solution of ordinary lye severely burned the foliage and 

 caused many leaves and squares to fall. It also seemed to scar the 

 unopened bolls severely and the plants almost immediately started 

 to put on a new growth. The caustic nature of the solution was also 

 objectionable. 



A 2% solution of hydrochloric acid burned some leaves and caused 

 about 40% of the foliage to drop, but in two days' time an abundance 

 of new foliage and fruitage was being put forth. 



A 3% solution of white arsenic in water, dissolved by long contin- 

 ued boiling, killed the cotton plants outright and no "second growth" 

 appeared at any time after spraying. The larger bolls were however 

 forced open almost at once, with the result that the lint and seed had 

 no opportunity to mature. 



A solution containing 5% of white arsenic and 3% of carbonate of 

 soda did not produce effects materially different from those produced 

 by the 3% arsenic solution. All the foliage was kiUed, the larger 



