322 PREVENTIVE AXD REMEDIAL MEASURES 



were nearly full-gi'own. The most successful results were obtained 

 by the use of iron .sulphate. It was found that the breeding of 

 the house-fly in horse-manure could be effectively controlled b}^ 

 spraying the manure with a solution of iron sulphate. A solution 

 of two pounds of iron sulphate in one gallon of water for each 

 horse per day was used. It was calculated that the average city 

 horse produces about fifteen pounds of manure per day and the 

 heavier draught horses produce twenty to thirty pounds per day. 

 The amount to be treated Ls, of course, much less than this as the 

 horses are out of the stables a large proportion of the day. The 

 average cost of treatment in Illinois would work out at less than 

 one penny (one and one-half to two cents) per horse per day. Not 

 only is the iron sulphate stated to deodorize the manure but it 

 does not injure its manurial properties. In fact, it is extremely 

 probable that it increases the fertilising properties of the manure. 

 Unfortunately, at the time of Avriting we have no experimental 

 evidence as to the effect of this and other insecticides on the 

 fertilising value of the manure. It is anticipated that investiga- 

 tions on this aspect of the question will be carried on^ 



It is claimed that the treatment of the manure with equal 

 parts of acid phosphate and kainit will repel the flies and prevent 

 their oviposition. Such treatment would certainly increase the 

 fertilising value of the manure. 



One is frequently asked how the farmer is to undertake the 

 control of the house-fly about his premises when he is compelled to 



^ Since the above was written I have carried out a series of experiments in 

 August and September, 1913 (see Journ. Econ. Ent., vol. 7, p. 281), with a view to 

 obtaining information on this aspect of the problem. It was found that the 

 greatest mortality was produced by chloride of lime scattered on the manure as it 

 was piled ; this was more fatal than iron sulphate solution. 



Dr L. 0. Howard lias kindly permitted me to secure the results of a series of 

 experiments carried out by the Bureau of Entomology, assisted by the Bureau of 

 Chemistry, of the U.S. Department of Agriculture, Washington, D.C., during the 

 summer and fall of 191.S to discover an insecticide which was not only cheap 

 enough for tlie farmer to use but wliich also did not injure the fertilising properties 

 of the manure. It appears that borax (sodium borate in the crude form) used 

 either in the j)owdered form (2 lbs. to 8 bushels of manure) or in solution (one- 

 eighth of a pound to one gallon of water, using 40 quarts of the solution to 8 

 bushels of manure) gives the liest results. The full report of this investigation 

 will be published shortly by the U.S. Department of Agriculture, to which impor- 

 tant report the reader should refer. 



