The first is the treatment of the manure pile with chemical substances
which will kill the eggs and maggots of the house fly. The Bureau of
Entomology, in cooperation with the Bureau of Chemistry and the Bureau
of Plant Industry, has conducted a series of experiments in which a
large number of chemicals were applied to infested manure and
observations made, not only on their efficiency in killing the maggots
but also as to their effect on the chemical composition and bacterial
flora of the manure. The object was to find some cheap chemical which
would be effective in destroying the fly larvæ and at the same time
would not reduce the fertilizing value of the manure.


TREATMENT WITH HELLEBORE.

Of the numerous substances tried, the one which seems best to fulfill
these conditions is powdered hellebore.[10] For the treatment of manure a
water extract of the hellebore is prepared by adding 1/2 pound of the
powder to every 10 gallons of water, and after stirring it is allowed to
stand 24 hours. The mixture thus prepared is sprinkled over the manure
at the rate of 10 gallons to every 8 bushels (10 cubic feet) of manure.
From the result of 12 experiments with manure piles treated under
natural conditions it appears that such treatment results in the
destruction of from 88 to 99 per cent of the fly larvæ.

Studies of treated manure indicated that its composition and rotting
were not interfered with. Furthermore, several field tests showed that
there was no apparent injury to growing crops when fertilized with
treated manure.