- 59 - 
Mclndoo and Sievers (188) in 1924 reported numerous tests of cube 
and derris in the fonr of dust s , and alcoholic and aqueous extracts, agains' 
unidentified aphids designated as Aphis spy). A, B, C, D, and E, In 
general these preparations were highly effective. 
Carlos (47) in 1926 reported that. derris as a contact or external 
poison, rath or "without the use of soap as a spreading agent, had been 
found effective against aphids in as low a dilution as 1 pound of root to 
400 gallons of water, which represents a proportion of 0.025 percent, 
Aphids are some of the chief insect pests Which can be easily exter- 
minated by the application of insecticides containing derris or its 
products. One interesting property of derris as a killing agent is that 
the effect lasts for a considerable time. Leaves sprayed with a solution 
containing derris preparations will remain poisonous to insects for many 
days , 
William Cooper and Nephews, in the February 1926 issue of Florida 
Entomologist, advertised Derriscl, stating that it was a new aphid spray 
having no odor, being nonpoisonous and pleasant to use, did not require 
soap, could be mixed. with other sprays, and could be used with hard or 
soft water. 
The Deli Proefstaticn (68) in Medan, Sumatra, in 1927 reported that 
derris was satisfactory for the control of aphids, but Derrisol was found 
ineffective at 1:400, although it was claimed to be effective at 1:800. 
TJeotcn at 110 gm. plus 22.0 gm. of soap per 40 imperial gallons 
killed 100 percent of arrowhead aphids, and at half this concentration 
nearly all were killed. Neoton at l/2 pound per 40 imperial gallons of 
xvater killed 100 percent of unidentified aphids,— Institute Physical and 
Chemical Research (162) in 1927, 
KcDaniel (186) in 1928 recommended Derrisol as a contact spray 
for use against aphids and Metcalf and Flint ( 193 ) in 1920 summarized 
current information on derris, which they recommended for aphid control. 
Dammerman (61) in his book, "The Agricultural Zoology of the Malay 
Archipelago," published in Amsterdam in 1929, mentions derris as having 
come much into use as an insecticide. 
t 
To prepare the insecticide the roots of derris are pow- 
dered, and the product _is now on the market. It is not of 
such a high value as was first expected, but being cheap in 
our region it may be found a useful substance. For making a 
spray, fresh roots are macerated with water, as a rule a 1- 
percent solution of derris is found most satisfactory; a 
stock solution is made by placing 1 kg. of comminuted roots 
in 10 liters of water in a vrooden vessel, the solution 
standing over for 1 night; the stock solution after being 
strained through a cloth is; diluted 1:10. But as it is 
impossible to ascertain the exact content of the toxic sub- 
stance in a solution this insecticide is comewhat unreliable. 
