REPORT OF J. P. STELLE. 
[31] 
TI1K YEAST FERMENT REMEDY. 
Obedient to orders in " Supplementary Instructions" I put this proposed remedy for 
the Cotton Worm to many careful tests, employing three grades of yeast, or w ferment," 
in my experiments. No. 1 was a duly prepared yeast obtained from a brewery; No. 
2, the same, obtained from a bakery ; and No. 3, a preparation made by myseli after 
Professor Willet's plan as laid down on page 71 of Bulletin No. 3. The yeast was di- 
luted with wat.r to various strengths, and sprinkled upon the plants and worms, both 
In the open field and under gauze-covered boxes. The boxes used were large dry 
goods boxM from which both top and bottom had been removed. They were placed 
over living plants in the field that had been liberally stocked with worms, and sprink- 
led w ith ili. i>]« par. iiion.s, alter which a thin cotton gauze, as mosquito barring, was 
tacked over the top of each. 
The closest possible attention was given to these experiments through an ample 
lapse of time for their penfeot development. Nothing resulted to indicate that the 
remedy w as of any value w hatever. 
PYRETHRUM POWDER. 
The powder used by me in my experiments was the California preparation some- 
times seen upon t he market as " IJuhach." I began operations by inverting two glass 
tumblers upon several thicknesses of soft paper, and placing under No. 1 live grains 
of p\ n thrum powder, dry, and under No. 2 the same quantity mixed with water to 
a thin DMte. Next I placed under each tumbler two lively Aletia moths taken from 
my breeding-box. The moths flew up and took positions immediately under the bot- 
toms of the inverted tumblers. 
One minute, all the moths were seen to be shaking or twitching their wings. Five 
minutes: all had fallen to the paper. When I struck upon the tumblers with my hand 
they fluttered up, hut immediat. I\ fell hack again, having apparently lust the power 
of holding to the glass with their feet. Fifteen minutes-: both moths in No. 1 were 
unable to fly up when I struck upon the tumbler, but lay upon their backs and moved 
their feet sluggish 1\ , as if in the act of walking. No. flew up the sides of the tum- 
bler and fell back as usual. Thirty minutes: No. 9 could rise no more; each of the 
four was lying upon its back, slowly moving its feet. In six hours all were dead, 
No. 1 dying about half an hour sooner than No. 2. 
This seems to prove that the dry powder is more prompt in its action than when 
moistened with water. 
At early twilight I closed my windows and turned loose in myroomsix lively Aletia 
moths, after having dusted upon t He head and thorax of each a very small quantity 
of dry pyrethrum powder. They flew up and settled about the ceiling and windows. 
live minutes: each showed that peculiar twitching of the wings that had been seen 
early in tho course of the preceding experiment. Fifteen minutes: three were down 
on t he floor unable to rise. Twenty-five minutes : all were down and helpless. I col- 
lected them iu an open wash-bowl ; next morning all were dead. 
Sprinkled two rows of cotton running across a square acre, with pyrethrum powder 
in water at the rate of one-fourth of an ounce to the gallon; also, two rows with the 
same at the rate of half an ounce to the gallon. The plants were heavily stocked 
with worms in almost every stage of growth, it being late in tho season when the 
broods were not murked with much regularity as to time. Tho weaker solution 
thinned out the worms somewhat, but did not give full satisfaction; the stronger 
solution entirely cleared the plants — next day not a living worm was to bo found upon 
the rows sprinkled with the stronger solution, though there were plenty of dead ones 
to be seen, usually upon the ground. 
1 made a dusting implement by fitting the pipe of a small hand-bellows into a small 
tin box, and perforating the top of tho box with many minute holes. A dry powder 
placed in the box could be forced through the perforations by working the bellows 
with care, thus enabling one to spread it quite thinly and evenly over the leaves of 
plants. With this I dusted two worm-infested rows of cotton with dry pyrethrum 
powdt r unmixed with anything, at the rate of about one pound to tho acre, throwing 
it as much as possible against tho undersides of the leaves. This brought no satis- 
factory results, which was, I take it, on account of the extreme lightness of tho pow- 
der preventing it from flying with force sufficient to stick to the leaves, and also en- 
abling a very large proportion of it to float off upon the air. I subsequently applied 
it in the same way mixed with dry London purple at the rate of one pound of the 
purple to four ounces of pyrethrum. This gave it weight and consequently a better 
Btii king capacity. The result was very good — in from two to three days not a worm 
was to be seen on the plants. 
I conducted man y experiments with pyrethrum looking to a fixing of its volatile prin- 
ciple, so that it might be applied in the open field and made more lasting in its effects. 
