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 8 bushels of manure, or about 1 pound per 16 cubic feet. Best
results were obtained when the borax was applied in solution, or when
water was sprinkled on after the borax had been scattered evenly over
the pile. Borax is not only effective in killing the larvæ, but when it
comes in contact with the eggs it prevents them from hatching. When
applied at the rate of 1 pound to 16 cubic feet it was found to kill
about 90 per cent of the larvæ, heavier applications killing from 98 to
99 per cent.

Borax has no injurious effect on the chemical composition or rotting of
the manure. However, when added in large quantities with manure to the
soil it will cause considerable injury to growing plants. A number of
experiments have been conducted to determine the effect on crops of the