- ?.<i - 
GiuGon ('':!) iii 1327 Teported. that powdered derris root has lethal 
pro;;/e:;ti!jc \ihen used against culicine mosquito larvae. When dusted on 
the curface of v.'ater c on t.';.inint;, larvae of Aedes vexans Mgn. this material, 
either alo.ie or in confoinaticn --.'.'ith an inert filler, ^vas found to destroj^ 
the larvr',e in a few hours even ■'•'hen used at tne rate of only 2 or 3 pounds 
of derric to the acre. 
Ho\/:ird (102) in 192? reported that tests v;i"th insecticides againct 
cii-ttlo .ji-ubs nad.e at Burkes Garden in Virginia indicated that .powdered 
derric root v/ill give a high percentage of kill if applied and brushed 
in at intervals', of about 20 days, 
Locn;irns (5b) in 1927 ror)ortcd that on the S^:ijaa.tra. East Coast 
cabbage groi/ors are mixing lead arsenate ^vith th:; usual derris solution, 
"TJo can report that a derric. finsnon si on in v/atcr against cabbage 
caterpillar" .;;.avc 'anfavorablc re suit r;, Cn the other hand, we have ob- 
tained c;ccollont r( s'O-ltG if fincl-- pulverised aorris was extracted v/ith 
alcohol, T.xc practical concliinion is that addition of a water suspension 
of dori'is or dorri;-. rooto to a colxition of lead arsenate is wholly useless 
since the l/^ttcr, -fith tno addition of soao, io satisfactory." 
Van dor ilcor llohr (67) in 1;.'27 reported that My su p persica e Sulz. 
is Q. serious jje^t of tobacco in Deli, S":unatra, The seed beds are infested 
fron the adjacent forest:;, anr' the young plants in the field are either 
infested in the s-a^i^e v/a:' or by the introduction of infested seedlings 
from the beds. If the beds are very badly infested, the seedlings sho\ild 
be destroyed or dipped in derris solution, ex'oeriments having shovm that 
this does not harai then. In the plantations a d.aily watch should be kept 
for the first traces of infestation. Spraying v/ith a solution of derris 
is advised. The applica,tion must be repeated after 4 to 5 da^rs. 
Parman ct al. (74) in 1927 j-eiDortcd results of chcmotropic tests 
with ':-]\c scrow-i7orm fly, A commercial derris powder repelled 95 percent 
of the screw-worm flics visiting a bait of beef liver. This is about the 
same f : gure as that obtained with pyre thrum powder. 
Roar:: ct al. (8?) in 1927 reported that derris powder when undiluted 
rcpcll.-d 95 percent of t}ic screw-worm flies visiting fresh beef liver, 
and a'hcn dilv.t^-d v;itn 9 -larts of kaolin it repelled 38 percent. 
Sonan (87) in 1927 re.-.ortcd tho.t spra: ing with derris and soap 
proved veiy effective against the following pests infesting tea plants 
in I'ovuov.a: Lymantrii dr. , Suproctit-. pr.eudoconspe rsa Strand, E. serice a 
'.Tilonan, Per the sia tai^.a-n .a Shir,, P, scintillans ^i7alk. , P soudo dura 
dasychiroi. des Str.and, Clone mendosa Hbn., ITotolo-ohus posticus Walk,, 
Stilpnotia c^'gana. Hoore, and Ai-ctornis al b.a Eremer. 
In bis annual re-port as entomologist of the Federated Malay States 
Dep.;>.rtuent of Agriculture (31) for 1927, Corbctt mentioned investigation 
on the insccticidal value of derris (in collaboration v/ith the agricultural 
chemist) as one of the main researches of the division of entomology. 
