INJURIOUS TO CABBAGE AND CRUCIFEROUS CROPS 355 



they become established in the root. Hellebore decoction is made 

 by steeping 2 ounces of powdered hellebore in a quart of boiling 

 water for half an hour, and then diluting to make a gallon of liquid. 

 It may be kept in the concentrated form, but should be thoroughly 

 stirred before using. It is applied in the same manner as the car- 

 bolic emulsion. Both these mixtures may also be used against 

 maggots on radishes and onions by making thorough applications 

 along the rows. 



The surest method of destroying the maggots on the roots is by 

 the use of carbon bisulfide (see page 57). This is entirely practi- 

 cable on a few plants, but has not come into general use on a large 

 scale, as no satisfactory tool for its injection into the soil is avail- 

 able. A small hole should be made with a dibble 4 to 6 inches from 

 the infested stem, and a teaspoonful of carbon bisulfide injected and 

 the hole tightly closed with earth. If made too close to the plant 

 the roots will be injured. The fumes kill the maggots by permeat- 

 ing the soil. Where plants are badly infested injection on two 

 sides may be necessary. The material will cost about $1.00 per 

 1000 plants. Professor Slingerland describes an injector, no 

 longer made, but similar tools are for sale by dealers in agricul- 

 tural implements in France, and might be made by any machinist. 



The Imported Cabbage Worm * 



Probably the worst pest of the cabbage and one of the best- 

 known garden insects is the common cabbage worm, whose parent 

 is the common w r hite butterfly. It is an old European pest and 

 was imported near Quebec, Canada, about 1860, whence it spread 

 to New England, reached New York in 1868, Cleveland, Ohio, by 

 1875,. and the Gulf States by 1880, and has since spread to all parts 

 of the country. 



The butterflies are among the first to emerge in early spring. 

 They are white, marked with black near the tip of the fore-wings, 

 which expand nearly 2 inches. The female bears two black spots 



* Pontia rapce Linn. Family Pieridae. See F. H. Chittenden, Circular 60, 

 Bureau of Entomology, U. S. Dept. Agr. 



