20 BULLETIN 245, U. S. DEPARTMENT OF AGRICULTURE. 



effect is noticeable from the experiments at either New Orleans 

 or Baton Rouge. 



The cooperation of Mr. George L. Tiebout, of the Louisiana Experi- 

 ment Station, Baton Rouge, and of Mr. W. G. Taggart, of the 

 Audubon Park Sugar Station, New Orleans, in connection with 

 these tests was of great assistance. 



As chickens and other farm animals are known to peck at, or 

 consume, certain parts of manure, tests were made by Mr. E. R. 

 Barber, placing hellebore-treated manure in coops with chickens 

 and using as controls chickens in a coop with untreated manure. 

 Thirty-eight one-hundredths of a pound of powdered hellebore was 

 mixed with 4 bushels of manure and placed in one coop with four 

 chickens, and evexj three days another lot of the manure similarly 

 treated was placed in this coop. The manure which was used 

 contained fly maggots, consequently the chickens were eager to peck 

 through it. In addition, the chickens, in both cases, were fed on 

 cracked corn and were given fresh water. The appearance of the 

 chickens was noted daily, and the test has been conducted for several 

 weeks with no apparent ill effect due to hellebore. 



SUMMARY. 



The larvicidal efficiency of both inorganic and organic substances 

 was tested and bacteriological and chemical examinations of horse 

 manure to which many of these substances were applied are reported. 



The following inorganic substances were tried: 



Arsenical dip. 

 Chlorid of lime. 

 Epsom salts. 



Lime-sulphur. 

 Sulphuric acid. 



Of these substances arsenical dip was the only one which when 

 used in amounts considered practical destroyed the larvae of the 

 house fly. Because of its poisonous nature the use of arsenical dip 

 as a larvicide is not recommended. 



The following organic substances were tested: 



Formaldehyde. 

 Nitrobenzene. 

 Oxalic acid. 

 Pyridine. 



Aniline. 

 Beta-naphthol. 

 Cresylic acid. 

 Para-dichlorobenzene. 



Aniline, pyridine, and nitrobenzene, when used in certain dilu- 

 tions, gave satisfactory larvicidal results, but the cost precludes 

 their use. 



The larvicidal action of the following plant materials was tested: 



Plant material containing saponin — 



Corn cockle (Agrostemma githago). 

 Agave (Agave lecheguilla). 



