New YorK AGRICULTURAL EXPERIMENT STATION. 199 
ARSENITE OF LIME. © 
Excepting paris green, the most popular insecticide for use on 
potatoes is white arsenit applied in the form of arsenite of lime. 
The insecticidal properties of white arsenic have been known for 
more than fifty years.° In 1871 Saunders and Reed* in Canada 
tested it on potatoes for the Colorado potato beetle. It was mixed 
with flour and applied’ dry. The results indicated that when 
applied sufficiently strong to kill the beetles it caused more or less 
injury to the foliage. Because of its caustic properties it was 
rarely used until after the publication of Kilgore’s formula in 
1891. Kilgore recommended’ “ boiling together for one-half hour 
in 2 to 5 gallons of water: 
1 pound commercial white arsenic 
2 pounds commercial lime, 
and diluting to required volume, say 100 gallons.” In this way 
the arsenic is changed into insoluble arsenite of lime and made 
safer to use on foliage. 
In 1897, Kedzie of the Michigan Agricultural College published 
what has come to be widely known as the “ Kedzie® formula.” It 
is essentially as follows: 
See Rem en RLy paeheesre nia se Peon scs Ml sha x) <p dcaced cao agiado susnener eae 2 pounds 
Pe a, WA SIE SSO). a so coiis. soa fon Sho.iefone-oie ete ie els reel e 8 pounds 
Water che 6) ee “es 6 se 2 ee 6 Siete o 62 e/'e, 5 0 6 oer ee eo @ ry Re Oe a eS 2 Ga I] Ons 
Boil 15 minutes or until the arsenic dissolves, leaving only a 
small quantity of muddy sediment. Replace the water lost in 
boiling. This makes a stock solution of arsenite of soda which 
may be placed in tightly stoppered jugs and kept on hand for 
use as needed. In preparing the spray mixture use two pounds of 
freshly-slaked lime with each pint of the stock solution in the 
desired quantity of water or bordeaux mixture. The arsenite 
of soda and the lime unite to form arsenite of lime. The arsenite 
in one pint of the stock solution is equivalent to four ounces of 
paris green. 
®Lodeman, HE. G., Loc. cit., p. 75. 
*Saunders, W., and Reed, E. B. The Canadian Entomologist, 3:46 July, 
1871. 
* Kilgore, By, Ws, Loe. n Clty De «7. 
*Kedzie, R. C. The M. A. O. Record, March 9, 1897. A verbatim copy 
of this article may be found in Bulletin 152 of this Station, p. 300. 
