June, '23 
leach: janpanese beetle on golf greens 
313 
control for the larvae in turf. A satisfactory kill was obtained by this 
method, and according to his published results, the injury to grass was 
negligible. The writers’ subsequent experience with this material 
corroborates the results secured by Davis as far as grub kill is concerned 
but in our experience the material is decidedly toxic to the grasses of 
meadows and golf greens. It kills practically all of the fine grasses and 
clover in meadows, and completely burns the fine grasses used in golf 
greens. 
In connection with the above experiments the writers carried on 
tests in 1921 using a plain mixture of carbon disulfide in water, the 
mixture being maintained by agitation in a tank and run out thru hose 
on to the turf. The grub kill by this method was not entirely satisfac¬ 
tory, but it was noted that no injury resulted to the grass; in fact the 
material was decidedly stimulating in its action. 
Under these circumstances the work with cyanide was dropped and 
the experiments were confined to a thorough testing of carbon disulfide. 
It was soon found that a plain mixture of the material in water was un¬ 
satisfactory, due to the uneven dispersion of the carbon disulfide 
thruout the water even when agitated. 
The writers therefore began a study of carbon disulfide emulsions, 
using various solutions of soaps as emulsifying agents. It was found 
that a fairly stable emulsion could be made with soaps in general, but 
the best emulsion, from all standpoints was obtained by using resin-fish-oil 
soap as follows: add 12.5 grams resin-fish-oil soap to 87.5 cc. of water 
and heat until dissolved; allow solution to cool; place solution in 
flask or butter churn and add 250 cc. of carbon disulfide: agitate until 
the ingredients emulsify, this condition being obtained in a few minutes. 2 
The emulsion proper is white in color, and the consistency of thick cream. 
When added to water it diffuses evenly and stays in suspension indefinite- 
ly- 
Tests were made with this material using various concentrations and 
various amounts of liquid per square foot of turf treated. For instance, 
500 cc. of emulsion was added to a 50 gallon barrel of water 3 and stirred 
in with a paddle. The solution was then flowed out into the turf by 
means of a hose and “Ross” watering nozzle, the liquid being applied to 
2 Before making large quantities of this emulsion it is advisable for the novice to 
experiment with the emulsification of small quantities of the ingredients in an 
Ehrlenmeyer flask in order to observe the phenomenon. 
3 This concentration is approximately one liquid ounce of carbon disulfide to 4 
gallons of water. 
