- 27 - 
and Later died. Atjainrt- the above insectc the product was used at the 
rate of 100 Gram:' ir 300 liters of water, Against caterpillars, 100 
grains to 45 liters can be usod, if ^ pounds of any cheap soap is admi.red, 
Sprayiiig ill sumner supijresses later generations of these irdtes, wnich are 
then rather lar^e, as v/ell as the irksome vine cicada. 
Mention is made of derils in the report of the Committee ou Policy'' 
of the jAnerican Association, of Economic Entomclogists e.t its 1927 raeeting, 
Gibson (4.'2), chairman, stated tha,t various new spra,y mixtures containing 
extracts of pyrethrum and derris have been tested as substitutes for 
nicotine and the results have been favorable in mo^t oas'"s. Under 
Toxicity Investigations, it is mentioned that derris is one of the contact 
insecticides v/hich havo boen investigated. 
Bani^c (4) in 192? reported the use of the decoction of the roots 
of D erris clliptica against caterpillars of the diamond-back moth, 
P lutella in aculipenni s Ciirtis. Because it is not entirely effective, 
load arsenate is naxed v/ith it. 
31icck and Baudot (8) in 1927 roviev/ed the work of Bishopp ct al, 
(6) on derris against ox warbles. 
Caesar (15) in 1927 included derris with arscnicals and sodium 
fluosilicatc ijindor the classification "Stonach Poisons. " It is described 
as "a li^;ht, bro'm. jjowdGr made from the roots of certain shrubs g;rov.'n 
in the Par East, osTjocially in the Mala^' peninsula. It is supposed to 
be both a contact and. stomach poison and when used as a dust is usually 
diluted v'ith air-r.lajced lime or Iiydrated lime or gypsum in the proportions 
of about 1 part of bulk to 20 or even 40 parts of the diliient. As' a spray 
it is quite harmless to foliage even with v/ater alone. It is a good 
insecticide against a considerable number of insects but not against all, 
UnfortUiiately it is even more difficult to secure than sodium fluosilica,te, 
though it T/^11 likely be put on the market in the comparatively near 
future , " 
The Deli Proef station (23) in 1927 reported that derris extract 
was satisfactorj- for the control of aphids on tobacco and caused no 
burning of the leaves. These derris extracts (suspensions of the mill::y 
sap in water) su^jplied "oy the Deli Proefstation to tobacco growers 
retain their toricity for at least 1 year when kept in. v;ell-closod 
barrels. Decomposition occurs in open vessels and in those not 
hermetically closed. The suspension becomes gray or nearly black, 
develops the odor of iij^drogcn snlnhide, and loses effectiveness. 
Contact v;ith iron is stated to bo undcsiraole. 
Donnir (24 and 25), in United States Patent 1,621,240, issued 
March 15, IOC 7, and in Reissue 18,667, issued November 22, 1932, stated 
that an alcoholic extract of cube js eight times as effective as 
similar derris extract vhen sprryed on the cotton aphid, 
Fulraek (2?) in 1927 reported the use of a 1-porcent water extract 
of the roots of Dcrri s clliptica for the control of plant lice on tobacco. 
