Many experiments with mixtures of commercial fertilizers were tried to
determine whether fly larvæ would be killed by any substance the
addition of which would increase the fertilizing value of the manure. A
mixture of calcium cyanamid and acid phosphate was found to possess
considerable larvicidal action. Several experiments showed that 1/2
pound of calcium cyanamid plus 1/2 pound of acid phosphate to each
bushel of manure give an apparent larvicidal action of 98 per cent. The
mixture in the form of a powder was scattered evenly over the surface
and then wet down with water. The use of this mixture adds to the manure
two important elements, nitrogen and phosphorus.