178 EXPERIMENT STATION. [Jan. 



this treatment. The material for 1 acre would cost about $10, 

 and the cost of labor, making and applying it would be about 

 $12 or $14 more. The total cost for three applications to an 

 acre of onions would therefore be $60 or more, and would make 

 this treatment too expensive, even if it were effective. 



€arhoUc Acid Emulsion. — This was prepared as follows: 

 soap 1 pound, water 1 gallon, crude carbolic acid 1 pint; dis- 

 solve the soap in water (boiling, to hasten solution) ; add the 

 carbolic acid and churn as for kerosene emulsion until a creamy 

 substance thoroughly emulsified has been produced. 



This was diluted to three strengths : 1 part to 30, 1 to 40 and 

 1 to 50 parts of water. It was applied in the same way as the 

 soap wash and the application repeated every other week. 



The results obtained so far as control of maggots is concerned 

 were the most satisfactory of any, decidedly checking the infes- 

 tation in the rows to which it was applied. On small areas it 

 would appear to be the most effective of the materials tested, 

 and its application to large fields would be determined largely 

 by its cost. This, for materials and labor together, was calcu- 

 lated at from $8 to $12 per acre, according to the strength used. 

 It would probably need to be applied at least three, and probably 

 four times, however, to be effective, which would make the total 

 cost from $35 to $50, It should also be borne in mind that 

 it was not an entire success, but only relatively so. So far as 

 could be determined the three strengths were about equally ef- 

 fective. 



General Conclusions. 



None of the materials tested proved satisfactory, though the 

 carbolic acid emulsion gave the best results. It was also one of 

 the less expensive treatments, costing from about $8 to $12 per 

 acre for each application. It is not improbable that some of the 

 other materials, applied frequently and with care, might prove 

 of some value, but only on small areas would this be possible at a 

 reasonable expense. 



The whole experiment indicates: (a) that no entirely effec- 

 tive method of controlling the onion maggot has as yet been 

 discovered; (h) that many of those thus far recommended are 

 of little value, at least on large fields ; (c) that the cost of treat- 



