178 EXn-RLAIEXT STATION. [Jan. 



this treatmont. Tlic 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. 



Qarholic Acid Emulsion. — This V\^as prepared as follows: 

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

 solv(; 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 v/as 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 

 l)v 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 i^robably need to be applied at least three, and j^robably 

 four times, however, to be effective, wdiich 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. 



GE^^EKAL CoiSrCLUSIONS. 



N^one 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 tliat some of the 

 other materials, a]^plied 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: (o) tliat 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- 



