13 
Tobacco in fine powder form dusted lightly on very young plants 
serves both as a repellent and as a mulch, or fertilizer. It is claimed 
by some to deter the striped cucumber beetle; others report that it is 
not effective for this beetle. ; 
A successful fumigation or vaporization of a cucumber house 
infested with the melon aphis was made also in June, 1906, at Ana- 
costia, D. C. A different preparation was used, and 66,000 cubic feet 
of greenhouse space was fumigated, 22 ounces of the liquid, or 1 ounce 
to 3,000 eubie feet, being employed. The work was under the writer's 
direction and conducted by Mr. I. J. Condit, with the cooperation of 
Mr. J. W. Bryan, owner of the house. At the end of an hour and 
fifteen minutes, when the ventilators were opened and the greenhouse 
aired, the aphides were found dead and dying, and the cucumbers 
were unharmed. Eight evaporators were used in this instance, each 
holding a little less than 3 ounces of the liquid. It is quite probable 
that a considerably smaller amount of the preparation, say 1 ounce to 
5,000 cubie feet, with an all-night exposure, would have accomplished 
the same object. The cost of fumigation is not above $2.50 for a 
house containing 64,000 cubic feet. 
Caution.— Before fumigating an entire greenhouse with any sub- 
stance a preliminary test is always advisable to guard against acci- 
dents and to avoid waste of material. In the case of one liquid 
tobacco fumigant used at Washington, the preliminary test showed 
that, employed at the strength advised by the manufacturers (/. ¢., 
without dilution), it ignited in the evaporating pan instead of vaporiz- 
ing. This trouble was obviated by diluting the fumigant with half its 
amount of water, the further precaution being taken of placing a wire 
gauze beneath the pan and over the flame. In the case of some alcohol 
lamps used for this purpose the flame is apt to be too strong, espe- 
cially if placed too near the evaporator. This causes the glass to break. 
Brass or other metal lamps are therefore preferable. Unless the 
lamps and wicks are of good quality and fit properly, the alcohol is 
apt to ooze out around the cork and burn on the sides of the lamp and . 
thus, also, cause breakage. 
As a general rule it is best not to fumigate in drzg/¢ sunlight, and 
not when delicate foliage or flowers have globules of water on them. 
SPRAYING METHODS. 
Kerosene emulsion and soap solutions.—The melon aphis could be 
much more readily dealt with if it were not for its unfortunate habit of 
feeding on the under surface of leaves—which are often badly curled, 
as shown in figure 1—and for the further fact that in large fields, par- 
ticularly late in the season when the leaves are large, the vines grow 
so closely together, frequently becoming interlaced, that spraying by 
ordinary meansis impracticable. Underspraying is an absolute neces- 
sity, and a sprayer should be used fitted with an upturned elbow and a 
