2 BULLETIN 118, U. S. DEPARTMENT OF AGRICULTURE. 



amounts of manure, was not practical for use on a large scale. Chlo- 

 rid of lime, however, was found to be a good maggot killer, but 

 its action on the bacteria was not studied. Br. Howard (1911) 1 

 published an account of his own experiments and of the work of other 

 investigators. 



Prof. S. A. Forbes (Howard, 1911, p. 197), State entomologist of 

 Illinois, found that lime, borax, borax and sodium arsenate mixture, 

 iron sulphate, and carbon bisulphid — the last in closed-box tests — 

 were effective larvicides. 



Herms (1910) claims that many of the common insecticides are 

 more or less effective if used in proper concentrations and amounts, 

 but none of these can be applied with safety, as they are poisonous, 

 inflammable, or corrosive. 



In 1912 Prof. E. I. Smith (Smith, 1912, p. 64), then State ento- 

 mologist of North Carolina, found that 2 gallons of kerosene 

 sprinkled over 25 square feet of a manure pile gave no indication of 

 any larvicidal action. Acid phosphate proved entirely worthless 

 from the standpoint of killing the maggots, even when used at the 

 rate of 400 pounds to every 2,000 pounds of manure. Finely ground 

 phosphate rock (floats) had no effect on the larvae. A 4 per cent 

 formaldehyde solution thoroughly applied to heavily infested manure 

 piles did not destroy any maggots. 



This seems to be the extent of the experimental work, as reported 

 in the literature, up to the year 1913. It is evident that the chemical 

 treatment of manure has not received the attention which it deserves. 

 Moreover, Dr. Howard (1911) has pointed out that all these experi- 

 ments have left unanswered the question as to what effect the treat- 

 ment will have on the manure itself. No analyses were made to 

 determine how the chemical composition of the manure was affected 

 by the larvicides; nor were any field experiments carried out to 

 ascertain whether the fertilizing value of the manure was altered in 

 any way. 



MANURE: ITS ROLE IN FLY BREEDING. 



As stable manure is one of the most valuable fertilizers known, a 

 large number of investigations have been carried on to determine the 

 best means of utilizing as well as preserving it. In addition to its 

 content of nitrogen, phosphorus, and potash the value of manure de- 

 pends on the number and species of bacteria present, as well as on its 

 content of organic material which the bacteria convert into plant 

 food. Manure, when undergoing fermentation in the open, loses 

 some of its valuable nitrogenous constituents, especially ammonia and 



1 Authors and dates ia parentheses refer to " Literature cited," p. 26. 



