- 14 - 
An ointraent co-usisting of 1 part derris and 5 parts vaseline has also given 
iilnost 100 percent kill v/hen, the material v;as pressed into each hole. 
Mollrun|.q; (50) in 1923 wrote that in Suciatra the follov;ing prepara- 
tion had given good results a/^inst loaf lice on tohaccp: l-l/2 kg, fresh 
t-aoa root is mr.shed in 20 liters of water, which is diluted v;ith an equal 
volume of v/atcr for use.- 
1924 
The preparation of derris for use as an insecticide is doscrilDed 
by an anonymous writer in the booklet "Plant Diseases and Pests" of the 
British Empire Exhibition ( lO) , London, 1924. 
"Eor small caterpillars and suckling insects, where a simple 
v/ash is required, the derris spray can be made on the spot. Use 
• tlie following proportions: - derris root 4-5 lbs., soap 2 lbs., 
water 50 (Imperial) gallons. 
"Cut the derris root into smn,ll pieces and pound to a pulp 
in a mortar with a little t/ater. Inclose the pulp in a cloth and 
squeeze well in a larger quantity of water. To the extract obtained 
by t]:is process add the soap, v/hich has been dissolved in a little 
hot v/atcr. Then dilute to 50 gallons." 
The sr.mo information was given by the Federated Malay States De- 
partment of Agriculture (30) in 1924. 
Symcs (39) in 1924 reported that two proprietary derris extracts gave 
•highly satisfactory results r.gainst .the black citrus aphis in Rhodesia. 
Brittain (13) in 1924 described inscctary feeding tests made in Eiske 
trays v/ith potato beetle larvae. Arsenate of lead (paste) in the strength 
of 2 pounds to 40 imperial gallons v/as compared \-jith various contact poisons, 
namely, nicotine sulphate, fish-oil soap, and derris povrder, an attempt 
being made to use the last both as a contact insecticide and as a stomach 
poison. To tost the contact action of .derris (B) the insects v/crc placed 
in a wire basket and dipped in the solution and then drained and fed on 
unsprayed le.aves. To test the internal action of derris (A) the leaves 
v;ere dipped in the solution and fed to the insects. The experiments lasted 
for a v/eek, daily records being talcen. The most notable results of the 
tests were those obtained in the case of derris, v/hich in all strengths, 
ranging from 3 pounds to 100 imperial gallons to 1 ounce to 100 imperial 
gallons, o,nd v;ith both m.othods, destroyed 100 percent of the insects, in- 
cluding half-grov/n grubs, fully grown grubs, and adults. It seems certain 
that this material did not act as a stomach poison, because the beetles 
were foiuid dead in the A trays, v;ith no sign of any feeding. 
The extreme toxicity of this material to potato' beetles is shown by 
the fact that 1 v.-eek after this experiment was concluded a number of last- 
instar grubs v;ero placed upon untreated leaves in a tray. The next morning 
the insects vjcto found dead in the bottom of the tray v.'ithout ever, having 
