14 
Retarding evaporationMixtures of carbon bisulphid with other 
substances designed to retard evaporation have been made, and the 
pure liquid has been used by putting it up in gelatin capsules, which 
allow a slow evaporation; but as these methods have not given as good 
results as the use of the pure liquid they will not be discussed in detail. 
Many of the foregoing statements regarding the treatment of 
Phylloxera apply equally well to the treatment of other insects living 
underground. 
TREATMENT FOR ROOT MAGGOTS. 
Carbon bisulphid has been more or less successfully used for the 
cabbage root-maggot ever since 1880, when Prof. A. J. Cook experi- 
mented with it with such success that he began to recommend it. 
There is no doubt that its eflicacy varies considerably with the nature 
of the soil, and there is equally little doubt that many of the failures 
which have been reported in its use have been due very largely to 
improper or too tardy application. If the liquid comes in contact 
with the roots, it will undoubtedly prove fatal to the plant, but a 
considerable amount of the vapor will do no harm. If the remedy is 
delayed until the plants are badly wilted, it is very likely that they 
will not recover, even though the enemy be killed, but their death 
can not fairly be attributed to the carbon bisulphid. Some growers 
who have tested it thoroughly state that it will work on clay or sand 
without injuring the plants. It has been found fatal to the pupe as 
well as the larve. Mr. M. V. Slingerland, of the Cornell University 
Agricultural Experiment Station, investigated the subject in 1894? 
and his ‘*‘ experiments demonstrated that when properly applied the 
substance was sure death to the insects and did not injure the plants.” 
McGowen injector.—Some instrument was needed to facilitate its 
application, as the French pal-injectors are too heavy and too expen- 
sive. To fill this need, the McGowen injector was produced. This 
very convenient little instrument could be adapted to nearly all of our 
uses of carbon bisulphid for underground insects, but the writer has 
been informed by Mr. McGowen that the demand for it has been so 
small that he has discontinued its manufacture. 
Method of application— Whatever the instrument used, the treat- 
ment should be made in practically the same way. The hole should 
start 3 or 4 inches from the stem of the plant and run down obliquely 
to a point a little below the roots, where the liquid is deposited. The 
hole is then closed with earth and compacted by pressure of the foot. 
The dose required varies from a teaspoonful for each small plant to a 
tablespsoonful for large plants (4 teaspoonfuls=1 tablespoonful=1 fluid 
ounce approximately). One injection will be sufficient if made in time, 
but if delayed too long nothing can save the plant. The conditions of 

1See Bul. No. 78, Cornell University Experiment Station. 
