10 



the. young maggots are not able ro penetrate to reach their food, 

 even shonhl any fly be hardy enough to brave the white surface and 

 carbolic odor. The young plants seem to find no difficulty in grow- 

 ing through the lime coating. Tbe preliminary application of the 

 carbolic acid emulsion is hardlv necessarv. 



Kerosene and Sand. 



This mixture is made by adding t.j a pail of dry sand half a 

 pint of kerosene and mixing thoroughly. As with the rest of the 

 mat{>rials, the applications slioidd be begun early, made fre- 

 <piently and applied thoroughly around the plants in the case of 

 the cabbage and alojig the rows in the case of the radishes and 

 onmns. Make the first application as soon as the plants are above 

 ground, follow in five days or so wi^h a second, and later apply 

 at week intervals. The flies do net readily deposit their eggs iii 

 this mixture and if any maggots on hatching come in contact with 

 the kerosene they will be killed. This application is not so easily 

 made as the carbolized lime and is hardly suited for use on laroe 

 fields. There is also an element of danger to the plants and care 

 must be taken not to have more kerosene than is recommended, nor 

 to pile too much of the sand around the plant at one time. 



Poiirdered Tobacco. 



This has been used as a preventive with some success and in our 

 experiments appeared to protect treated plants to a certain extent, 

 even though applied very late. With this material, likewise, 

 timely, frequent and thorough applications are necessarv. The 

 fly undoubtedly does not care to deposit its eggs in the tobacco, 

 and if forced to do so the young larva should find a covering so 

 thorough that in attempting to reach a suitable feeding place it 

 would come into contact ^vuth the tol)acco, which, especially if wet, 

 would serve as a killing agent. The tobacco, in addition, is a 

 fertilizer, so that in any event its application would be of ad- 

 Tantage to the plant sufficiently great to pay for its use. It should 

 1)0 as finely ground as it is possible to get it. 



