14 
fungicide, and it operates also against different forms of bight and 
other diseases which may threaten the crop. 
Arsenate of lead serves the same purpose as Paris green, and for 
use against the Colorado potato beetle is still more valuable. Com- 
plaints have been made that several applications of Paris green are 
necessary during the season, and extra doses are required after each 
rain. Arsenate of lead is applied in practically the same manner as 
Paris green, but it contains less poisonous arsenical (60 to 70 per 
cent when dry), and being sold usually in the form of a paste it 
is used at a considerably greater strength—i. e., about 1 pound com- 
bined with 15 to 25 gallons of water or Bordeaux mixture. Being 
more adhesive, it adheres more firmly to the leafage and is much less 
likely to produce scorching.“ Its adhesiveness is still more enhanced 
by the addition of about the same amount, by weight, of resin fish-oil 
soap as of the arsenical used. 
The number of sprayings to be apphed will depend somewhat upon 
local and seasonal conditions. Two or three will ordinarily suffice 
for the spring brood, especially if apphed just after the eggs have 
hatehed, and the same number should be apphed for the second 
generation. 
Other arsenicals may be used if preferred. Among these are ar- 
senite of lime with soda, which has the merit of being as efficient as 
Paris green and lime and far cheaper. It is not on sale at the present 
time ready made, like arsenate of lead. Scheele’s green, similar to 
Paris green, is employed in the same way as the latter. 
Summary—To sum up the directions for the use of arsenicals, it 
should be said that arsenate of lead, because it can be purchased 
already combined, in paste form, which is preferable, takes first place, 
in the writer’s opinion, as a potatd-beetle insecticide. The mixture of 
Paris green, lime, and water is in nearly the same class, because the 
ingredients can be purchased anywhere. The dry Paris green mixed 
with air-slaked lime properly comes last, as it is less effective than 
the other mixtures and much of the material is wasted. 
Precautions to prevent poisoning.—In the use of arsenicals, as well 
as other poisons, care should always be taken to avoid accident. This 
‘an. be best accomplished by plainly marking the contents on all 
receptacles, such as bottles or packages, in which the poison is kept. 
In addition a “ POISON ” label, which can be obtained of any drug- 
gist, should be affixed. It is best also to keep such substances under 
lock and key. The utensils employed in the preparation of the mix- 
tures which have been discussed should be thoroughly cleaned after 
use. 
“Jn point of fact it can be used at the rate of 1 pound to 10 gallons without 
injury, but this proportion is not advisable, owing to the extra cost, and scorch- 
ing would be apt to follow its use on plants exposed to hot sunlight. 
[Cir. 87] 
