DESTRUCTION OF FLY LARV^ IN HORSE MANURE. 25 



outer edges of the pile, most of the borax should be applied there. 

 The treatment should be repeated with each addition of fresh ma- 

 nure, but when the manure is kept in closed boxes less frequent appli- 

 cations will be sufficient. Where the calcined colemanite is available, 

 it may be used at the rate of 0.75 pound per 10 cubic feet of manure, 

 and is a cheaper means of killing the maggots. In addition to the 

 application of borax to horse manure to kill fly larvae, it may be 

 applied in the same proportion to other manures, as well as to refuse 

 and garbage. Borax may also be applied to floors and crevices in 

 barns, stables, markets, etc., as well as to street sweepings, and water 

 should be added as in the treatment of horse manure. After estimat- 

 ing the amount of material to be treated and weighing the necessary 

 amount of borax a measure may be used which will hold the proper 

 amount, thus avoiding subsequent weighings. 



WARNING IN CONNECTION WITH THE USE OF BORAX-TREATED MANURE. 



While it can be safely stated that no injurious action will follow 

 the application of manure treated with borax at the rate of 0.62 

 pound for 8 bushels, or even larger amounts in the case of some 

 plants, nevertheless borax-treated manure has not been studied in 

 connection with the growth of all crops, nor has its cumulative effect 

 been determined. It is therefore recommended that not more than 

 15 tons per acre of the borax- treated manure should be applied to 

 the field. As truckmen use considerably more than this amount, it 

 is suggested that all cars containing borax-treated manure be so 

 marked, and that public-health officials stipulate in their directions 

 for this treatment that not over 0.62 pound for 8 bushels of manure 

 be used, as it has been shown that larger amounts of borax will 

 injure most plants. It is also recommended that all public-health 

 officials and others in recommending the borax treatment for killing 

 fly eggs and maggots in manure warn the public against the injuri- 

 ous effects of large amounts of borax on the growth of plants. 



COST OF BORAX TREATMENT. 



The amount of manure from a horse varies with the straw or other 

 bedding used, but 12 or 15 bushels per week represent the approxi- 

 mate amount obtained. As borax costs from 5 to 6 cents per pound 

 in 100-pound lots in Washington, it will make the cost of the borax 

 practically 1 cent per horse per day. And if calcined colemanite is 

 purchased in large shipments the cost should be considerably less. 



