The Cabbage Root Maggot. 531 



first removing some of the earth from about the plants. It must 

 be remembered that its success will depend on the eggs or maggots 

 being hit with it. None of the cabbages in our experiment were 

 injured in the least by an application containing nearly twice as 

 much of the "acid, and there is but little danger of its injuring the 

 tenderest foliage of radishes, turnips or onions ; if any injury 

 manifests itself on these crops, dilute the emulsion with 40 or 50 

 or more parts of water, instead of 30. A Knapsack or a Wheel- 

 barrow sprayer would prove a very useful instrument in applying 

 the emulsion on a large scale. 



Whoever has tried this emulsion thoroughly report success, 

 and we believe it is the most successful and most practicable 

 method of treating radishes, turnips, or onions, yet devised ; for 

 plants of the cabbage tribe, other methods discussed further on 

 will prove more effectual. We hope this emulsion may be given 

 a fair trial by many gardeners and other investigators. In our 

 experience, it is more effective than the kerosene emulsion and 

 rivals the bisulphide of carbon treatment. 



CARBON BISULPHIDE. 



Prof. Cook was the first to experiment with this volatile substance on the 

 root maggots. In 1880, he used it for this purpose " with the happiest 

 results. A small hole was made in the earth near the main root of the 

 plant, by the use of a walking stick, and about 15 cubic centimeters of the 

 liquid poured in, and the hole quickly filled with earth, which was pressed 

 down with the foot. In every case the insects were killed without injury to 

 the plants " The next year, Prof Cook found that its use was not practica- 

 ble in radish beds owing to the great number of plants to be treated, thus 

 requiring so much liquid as to make it an expensive treatment ; he tried 

 making a few applications at short distances apart in the bed, but not with 

 satisfactory results. In 1884, some of Prof Cook's correspondents reported 

 that the substance sometimes injured the cabbage plants, and its efficiency 

 varied with the nature of the soil. The same year, Mr. Goff "found that 

 bisulphide of carbon applied to the soil about the roots of radishes, destroyed 

 the maggots that had not yet entered the root, but it had no perceptible 

 effect upon those within." 



In 1886, Prof. Cook reported before the Ingham Horticultural 

 Society that experiments at the College that year had showed 

 conclusively that, if carefully applied and used in time, it was 

 a specific against the maggots. Those who had reported that 



