February, '17] PARROTT: RADISH MAGGOT AND SCREENING 79 



Vice-President G. A. Dean: Is there any discussion of this paper? 



Mr. H. T. Fernald: Professor O'Kane has dwelt on the side of the 

 question deahng with the efficiency of the treatment against the in- 

 sects. Has he any observations to give us as to whether this treatment 

 had any effect on the plants involved? 



Mr. W. C. O'Kane: We have a lot of information, but I do not have 

 the data with me. 



Mr. H. T. Fernald: Several years ago we made tests of the carbon 

 disulphide method of controlling onion maggot by placing the material 

 in the soil near the young onion plants. We found it possible to 

 kill the maggots, in many cases. Taking our results in a general way 

 they corroborate those of Professor O'Kane as to killing them all, but 

 many of the treated plants were injured. 



Vice-President G. A. Dean: Mr. E. R. Sasscer will present the 

 next paper on the program. 



RECENT VACUUM FUMIGATION RESULTS 



By E. R. Sasscer, Bureau of Entomology, Washington, D. C. 



(Withdrawn for publication elsewhere) 



Vice-President G. A. Dean : Are there any remarks? 



Mr. R. a. Cooley: I would like to ask what provision has been 

 made for exhausting the gas from the large cylinders. 



Mr. E. R. Sasscer: The exhaust gas is passed through a solution 

 of sodium hydroxide. One firm passes it through a reclaiming hydrox- 

 ide and uses it twice. Another simply allows it to pass through and 

 lets it escape into the air through the roof. 



Vice-President G. A. Dean: We will now listen to a paper by Mr. 

 P. J. Parrott. 



THE RADISH MAGGOT AND SCREENING 



By P. J. Parrott, Geneva, N. Y. 



In western New York root maggots are very destructive to radishes, 

 and in clay soils, especially, this vegetable can no longer be grown with 

 any assurance that the plants will be free from injury. As screening of 

 beds has proven satisfactory for the production of seedlings of late 

 cabbage, experiments have been carried on by the New York Agricul- 

 tural Experiment Station iqr the past three years to ascertain the effects 

 of growing radishes under cheesecloth on the quality and growth of 

 the roots. 



