Par':g anf. Pierstorff ( 312 ) in I'^-V- r.?c';:n"iPnded derris nr cu":^ dust 
(0,5 to 0.75 percent of rnton^ne) or spra.y (^ povmdg of powdrr of U per- 
cent rotcnone content per 100 gallons '■f water) to 'ho appliod in Hay- 
when the "bectlrs ^.rp firpt o"bsorved. . . ■■: 
Phaf'don brassicao B'p.ly 
Iho Institntp of Phr<?ical and Che7!ical Rffsoarch (220) . in ^927 reported 
that lleoton (derris extract in fish oil), 1 pound in 60 irnp-^rial gallons of 
vratpr, killed 100 porcpnt of the adults and QO.percont of the larvae irl • 
the field in war:' w» at".er, "but when tho t-rmperature dropped (middle of S^^pt- 
en1:er in Jppan) the n.^rtality' o'f ooth forns -''Jror'r.ed to 60 percent,, l^p'-ton, 
1 p'^und in ^0 inp^^ripl gallons of water, killed 21.6 percent ^f the e^-es. 
Fhred-n c^chleariae (F,), a !nnet'=!rd beetle- 
Thompson ( 370 ) in 1932 reported that ^n^ spra.ring with a tlerris- 
soap'was.^, follovrod by flo'-^din.::, was cffegti-'e in checkin.a; the in,iurr b^'- 
this beetle in one localitj^ in Wales. An^th^-^r bed of water cress was' 
dusted v;ith der-is povrdrr, 'ut on account of the lare-e auantity of material 
reauired this method was discontinued ^nd the derris-soap wash was: spr^rrf'd 
on six '^r seven tines at intervals of about ? week. It w?s' concluded that 
spra:'inr:- in this vpy i<^ thoroughly eff-^cti^e as a control ne^^.sure, 
Edvrards ( ll^ ) in 1^3^ report'"d the results of experi'^ents carried 
out in England in 1*^)35 v'itla derris 'nd pyrethmr.'. insecticides for the c^mtrol 
of the mistrrd beetle. Insecticif -es tested comprised a derris "spray cont'^in- 
ing O.O'^'U percent of roten^ne with 0,05 percent of sulfonated lor'^1 as a 
s;oreader, tv/o derris dusts vrith respecti-e rotcnone contents of 0,2 ard '^,5 
■oercent, and a pyrethru'^ 'emulsi'^n c^ntainin^ ^.O*! percent of tiyr^^thrin I. 
Two arpllcatinr.s were nade, on June 2-- and July 5, respecti"^oly, on -nlots of 
'jniformly heavil,^- infested water cress. Counts were nade on July 10-, the 
weather in the interim ha->''inf^ be^-n warn and sunny. The treatment reduced the 
bretle popula.tion to an average of 22, U, 13»7, 3»1, sind 37*9 percent, res'^ect- 
ively, of that on the control plots, which a^era^ed 322 indi-'-idual'! p--r souare 
foot. The control e^i"^''"!"- '"'^7 the socnd dorris 'dust was considered, very satis- 
factory, but several disadvanta-ers vrould att-'^nd an indiscriminate use of 
derris duats in the beds. These include th^^ danc-T of poisoning fish in 
rivers or ponds to vhich tlie dust -night ■:*- carried, and the ^^ractical diffi^- 
culty of ensurin^t a thorough applies ti^n to the lovrrr leavo^^ whore th*^ bretles 
cn.'jrc.rr't'o in dull weather. 
These results were confirned by eirowers in S^'ith Waleq and Monnnuthshir 
in 1936, who obtained sufficiently f;oo6. c'ntrol vrith "err is dust of not less 
than 0.2-prrcent-rotr-n'^ne content apr^lied at intervals -^f !''• days in punny 
weather. 
Phaedon inccrtus Baly 
Noz\i anc. Sonoyana (j£7_ in 1^-2^ r-^con K^ndedt spraying with derris mix- 
tures for the control •of this chrys-^n^-lid feeding ^^n crucif ■■rous vec:etable'5 
in Jnpan. . " ■ . ■•■ 
Nakaya-ia, Masaki, end Tab'^shl (2^2) in lO"^"^ reco-^.^endpd a s^r-^" '-f 
about 1 fluid ryxnc^ "f derris soap [Neeton?] to 1 f;allon' of wat^r. 
