1913.] PUBLIC DOCUMENT — No. 31. 177 



this way. As the cost of soap enough to cover an acre once in 

 this way would be from $8 to $10, and the hibor involved would 

 come to about $14, three treatments, each costing from $20 to 

 $24, would manifestly be too expensive. 



Carbolic Acid and Lime {" Carholized Lime"). — The ob- 

 ject of this treatment is to cover the ground around each plant 

 with a coating through which the maggots cannot penetrate, 

 much as tarred paper discs act in the case of the cabbage mag- 

 got. The practical difficulty with it is that in cultivation and 

 weeding the coating becomes broken and therefore not effective. 



To prepare it, lime is slaked to a thick cream. Three pints 

 of this are added to a gallon of water, and a tablespoonful of 

 crude carbolic acid is stirred in. The mixture is then poured 

 along the rows to form a complete coating around each plant. 



The odor of the carbolic acid was very noticeable for some 

 time near the plants treated in this way. It was necessary to 

 repeat the treatment, however, after each cultivation or row 

 weeding, as in every case the coating was more or less broken 

 by this work. 



The results were far from satisfactory. Either the coating 

 was not sufficiently thick to prevent the maggots from passing 

 through it, or they went beneath it. In any case, the infestation 

 in the rows treated with this material was as great as in the 

 check rows. 



The cost of the material was not great, nor was the time nec- 

 essary to prepare it. Application, however, had to be carefully 

 made, and the total cost per acre for a single treatment would 

 be about $23 or $24. At least three applications would be nec- 

 essary following cultivation, which would make this treatment 

 too expensive. 



Kerosene Emulsion. — This material was prepared according 

 to the usual formula, and was diluted to three different degrees: 

 1 part of stock emulsion to 9, 1 to 14 and 1 to 19 parts of 

 water. It was applied in the same way as the soap wash and 

 repeated at intervals of from ten to fourteen days. No injury 

 to the plants at either strength was observed, nor did the differ- 

 ent degrees of dilution appear to affect the results as regards 

 the maggots. 



Little protection from maggots was found as the result of 



