DESTRUCTION" OF FLY LARVAE IN" HORSE MANURE. 



21 



manure. The low water-soluble nitrogen and ammonia results of 

 the controls may possibly be due to the unusual fermentation going 

 on in these two samples, as indicated by the peculiar odor. The 

 fact that, after grinding, the manure tended to cake or lump may 

 have prevented the usual amount of material from going into 

 solution. The bacterial counts in the cage experiments are higher 

 than the controls, and also higher than those of the open piles. This 

 is undoubtedly due to the artificial conditions of the cage experi- 

 ments. The increase of water-soluble nitrogen, ammonia, and alka- 

 linity has been found in all the borax-treated manure, both cage and 

 open-pile tests, at Arlington and New Orleans. 



In Table VII additional cage experiments showing the larvicidal 

 action of borax, dry and in solution, and calcined colemanite with 

 water, are recorded. Borax in small amounts, such as If pounds per 

 8 bushels of manure, destroyed 98 to 99 per cent of the maggots, 

 and calcined colemanite, even when 2 pounds per 8 bushels of manure 

 were used, showed the same percentage of larvicidal action. 



Table VII.- 



-Cage experiments showing larvicidal action of borates on fly larvw 

 in horse manure. 



No. 



Treatment of 8 bushels of manure; 10 gallons used whenever liquid was added. 



Total 

 number of 



flies 

 emerged. 



Series N: 



1.... 



2.... 



3.... 



4.... 



5.... 

 Series O: 



1.... 



2.... 



3.... 



4.... 



5.... 



6.... 



7.... 



Na-borate, dry powder, 2i pounds (no water added) 



Na-borate in solution, \ pound per gallon 



do 



Control (water) 



do 



Na-borate in solution, i' pound per gallon . 



do 



do 



Na-borate in solution, J pound per gallon . 

 do 



Calcined colemanite, 4 pounds plus water . 

 Calcined colemanite, 3 pounds plus water. 

 Calcined colemanite, 2 pounds plus water. 



Control (water) 



do 



12 

 1 



2 

 6,152 

 5,370 



5 



13 



68 



46 



50 



55 



165 



29 



3,069 



3,140 



RECENT EXPERIMENTS TO DETERMINE MINIMUM AMOUNTS OF BORAX AND CALCINED 

 COLEMANITE WHICH ARE EFFECTIVE AS LARVICIDES. 



Some recent tests at New Orleans to determine the minimum 

 amounts of borax and calcined colemanite which are effective have 

 shown that 0.62 pound of borax and 0.75 pound of calcined colemanite 

 are effective as larvicides, but when smaller amounts of either 

 are used their larvicidal value is reduced. It is therefore appar- 

 ent that 0.62 pound of borax and 0.75 pound of calcined colemanite 

 to 8 bushels of manure (10 cubic feet), with the addition of 2 to 3 

 gallons of water, are the minimum quantities of these borates that 

 will destroy practically all the fly maggots in manure. 



