The House Fly and How to Suppress It | Page 7

In cities, with better methods of
disposal of garbage and with the lessening of the number of horses and
horse stables consequent upon electric street railways, bicycles, and
automobiles, the time may come, and before very long, when window
screens may be discarded.
DISPOSAL OF MANURE IN RURAL AND SUBURBAN
DISTRICTS.
The control of flies in rural and suburban districts offers a much more
difficult problem. Here it is often out of the question to remove all
manure from the premises twice a week, and the problem is to find
some method of disposal or storage which will conserve the fertilizing
value of the manure and at the same time prevent all flies from
breeding, or destroy such as do breed there.

With this idea in mind, it has been recommended that stable manure be
collected every morning and hauled out at once and spread rather thinly
on the fields. This procedure is advisable from the point of view of
getting the maximum fertilizing value from the manure. Immediate
spreading on the fields is said largely to prevent the loss of plant food
which occurs when manure is allowed to stand in heaps for a long time.
This method will be effective in preventing the breeding of flies only if
the manure is hauled out promptly every morning and spread thinly so
that it will dry, since it is unfavorable for fly development in desiccated
condition. The proper scattering of the manure on the fields is best and
most easily and quickly accomplished by the use of a manure spreader,
and many dairies, and even farms, are practicing the daily distribution
of manure in this way. Removal every three or four days will not be
sufficient. Observations have shown that if manure becomes flyblown
and the maggots attain a fairly good size before the manure is scattered
on the fields, they can continue their development and will pupate in
the ground.
CHEMICAL TREATMENT OF MANURE TO DESTROY FLY
MAGGOTS.
During the summer months, when fly breeding is going on most
actively, the farmer is also busy and often can not spare the time to
remove manure regularly. The general practice, therefore, has been to
keep the manure in heaps located, as a rule, very near the stables. How
can fly breeding be prevented in such accumulations? As a result of
recent investigations, it is now possible to point out two methods which
are practical and effective.
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.
Since the solution is somewhat poisonous it should not be left exposed
where it might be drunk by livestock. It is quite safe to say that
chickens will not be injured by pecking at hellebore-treated manure.
This has been tested carefully. Hellebore can be obtained both in
ground and powdered form, but the powder gives the best results in the
destruction of fly larvæ.
[Footnote 10: Veratrum viride or V. aloum.]
TREATMENT WITH POWDERED BORAX.
Another chemical found to be even more effective as a larvicide is
powdered borax. This substance is available in commercial form in all
parts of the country. It has the advantage of being comparatively
nonpoisonous and noninflammable and is easily transported and
handled. The minimum amount necessary to kill fly larvæ was found to
be 0.62 pound per