- 13 - 
1931 
Uagel (84) in 1931 reported tests vrith an c.queoua solution of dipyri- 
dyl sulfate containing 40 percent of the dipyricSyls, and also with an 
emulsion containing 80 percent of dipyridyls, upon larvae of the llediter- 
rpne.an flour noth (Sp hestia lai eliniella Zell.). The more concentrated 
dipyridyl preparation exceeded nicotine sulfate (40 percent) in toxicity, 
Tvhich \Yas pro'bahly due to the presence of some neonicotine in the mixture. 
1932 
Austin, Jary, arid I'artin (7) in 1932 reported that when a commercial 
preparation of anahasine sulfate, g-j.aranteed to contain 35 percent of 
anabasine, was diluted 1:5,600 (=1:15,000 anahasine), the insecticidal 
efficiency against hop aphids, ?horodon humuli (Schr.), was equal to if 
not greater than that of nicotine at the same weight concentration. 
Sodium oleate or sulphite lye was used as a, spreader. 
Zalkind (l5l) in 1932 studied the effect of anatasine sulfate upon 
the beet louse, Aphis fabae. Tests were carried out in the fields, on 
second-year beet plants, the flower stalks of which were entirely covered 
with colonies of the beet louse; and in laboratories, using Koch cups 
where young as well as grown-up specimens of beet lice had been puifc on 
sugar beet lea.ves. A 35-percent solution of anabasine sulfate wa,s tested 
at concentrations in water of 0.01 percent to 4 percent. Zalhind con- 
cluded: 
1. As a contact insecticide for the beet louse, anabasine sulfate 
is not inferior to the best contact insecticides known. 
2. A 0.05-percent concentration of anabasine in wa.ter is the mini- 
miom dose producing 90 percent of mortality of the louse on second-year 
plants. This concentration destroys all the yotmg lice; only grown-up 
females survive. 
3. A complete destruction of ^''oung as well as of gro\7n-up lice en 
second-year plants was attained by a 0,1-percent anabasine concentration 
abundantly moistened. 
4. A 0.5-percent concentration of the anaba.sine solution produces a 
very prompt destruction of the louse. 
lor practical use Zalkind advised a 0.3-percent concentration cf 
the anabasine solution (equivalent to 0.1 percent of actual anabasine). 
1933 
Craig and Richardson (18) in 1933 reported the results of studies of 
the relative toxicity (expressed as the concentra.tion that killed 50 
percent in 24 hours) of 11 alpha- substituted N-me thy Ipyrroli dine com- 
pounds to Aphia rumicis L. The comuounds were made up with 0.25 percent 
of sodium oleate and applied as a fine spray to the wingless adults. 
