RESULTS OF EXPERIMENTS AGAINST THE CHICKEN MITE. 5 
NAPHTHALENE. 
Since naphthalene was efficient as a fumigant, it appeared that 
this material might have effect as a dust. Naphthalene of 40-mesh 
fineness was dusted in nest boxes at 100 per cent, 75 per cent, 50 per 
cent, and 23 per cent strengths. 
In the first of these tests it was efficient, in the second and third 
(with wiieat flour as diluent) moderately so, and in the last (with 
sand as diluent) inefficient. Pure naphthalene dusted on roosts was 
efficient in two out of four tests. A 4 per cent naphthalene in lime 
was inefficient in a roost test, while a 12 per cent preparation in sul- 
phur and lime proved moderately efficient when dusted in an infested 
coop. Coarse naphthalene was inefficient when dusted in two in- 
fested chicken houses, while a naphthalene of 40-mesh fineness was 
of slight value in a third. 
It appeared that naphthalene is efficient only in a small circum- 
scribed area where it may have a fumigation effect. In more open 
places it has a rather weak repellent effect. Dissolved in kerosene, 
the mixture was not more efficient than pure kerosene, but dissolved 
in gasoline the resultant mixture was more efficient than pure gasoline. 
In practice, dusting with naphthalene is not a feasible method for 
the control of the chicken mite. 
DEBRIS. 
Four infested chicken houses were dusted with the finely ground 
powder of the roots of Derris sp. Undiluted dust was efficient in one 
house and temporarily so in another. In a third house a 75 per cent 
dust was only moderately efficient, in a fourth test a 50 per cent dust 
was inefficient. Flour was used as a diluent. 
Derris powder is a remedy of value, but it would appear that two 
or more applications are necessary and that it loses its efficiency if 
diluted more than 25 per cent. Its action on larvae and adult mites 
is first to stupefy them, the insects dropping to the ground and dying 
after two or three days. The material is rather unpleasant to apply. 
PYRETHRUM. 
Finely ground flowers of Pyrethrum cinerariaefolium and P. roseum 
were efficient when dusted undiluted in a nest box and when applied 
in a chicken house in two applications 33 days apart. Another 
house was dusted once and a third twice (32 days between applica- 
tions). These latter tests showed only moderate efficiency, but 
conditions were very unfavorable in the house treated twice. 
Pyrethrum diluted with flour to 75 and 50 per cent strengths was 
inefficient in chicken houses. 
Pyrethrum is somewhat less efficient and less unpleasant to handle 
than derris-root powder. 
SABADILLA SEEDS. 
Finely ground sabadilla seeds (Schoenocaulon officinale) were effi- 
cient in treating an infested nest box. 
It appears probable that this material equals derris in efficiency, 
but no chicken house tests were made to determine this point. 
