- 30 - 
Hanilt'^n ( 172 ) in 19^?. rsvnvt^-: th^t strir..-d cnc^xm'C-r empties 
on cucimGr-rs wr^rr- c^ntrcllp-l l^G ■'■erc"nt c;' a g-oray cf ^ pounds of derris 
or cu'cr- rfovC.cT (^ PTCPnt of r^tenone) and U ^ou-nds of ropin-rr sidue 
enulsi'^n oer 100 gallons of vrater. Th.-= ?pr=>:' acts as a contact poisr^n 
or as a repellent, i^n or-^tles verr '^'bserv'-d later than 2 v/eeks after 
spraying. 
In laTjoratory tests derris^gj'psu'n dust containing 0.2 percent 
of roton'-^ne killed 100 percent' in 1 daj'. A dust containing 0.0^ percent 
of rotenone killed 20 percent and a dust containing 0,1 pprcent killed 
SO percent in 1 day. Field experiment « shovred this insect to "be very 
susceptible to derri?; dust. — Kelsall and Stultz ( 2U5 ) in 1937. 
C. L, Smith ( 3^9 ) in 1937 roT^orted that a spray of derris 'oow-''.«^r 
(U percent of rotenone) ^t 2 pounds p^r 100 gallons of water plus l-j/S 
poionds of coconut-oil sopp (anhydrous "basi?) killed 97 "^^crcpnt of striped 
cucu-mher "beetles on snuash plants confined in cheesecloth cages 2U hours 
after application. A l-percent-derri'5 dust gave 8S-percent kill. 
Ultrawet (a proprir-tary wetting agent consisting of water-solulDle 
sodium sulfonates of petroleuiTi hydrocarbons) did nr^t impro-^'-e the control 
of the striped cucunher beetle pro'^ided by cube dusts (0.75 "oercent ^f 
rotenone) or <=prays ("^ pounds per 100 gallons of wat'^r) ,- -Walkr-r (U06) 
in 1938, 
Dunlap and Tnrn'-r ( I06 ) in IQ38 reconmended a dust containing 0.6 
or 0.75 percent of r'^tenr.ne applied three or four ti-'os wepkly et the rate 
of 15 pounds oer aore. 
For the s^-c^nd-gen ^ration b'^etles a derris dust (l p'^rcf'nt of 
rotenone) sh'-uld be applied at lea = t twice a vrco'^z for a m-^nth. — Gp.nderson 
( iGg ) in 1938. 
Howord ( 192 ) in IQ'^S re-ncrt'd thet in -nrelinlnary tept<^ pgginst 
Diabrotica vitteta excellent control was obtained with a dust mixture con- 
taining 0.'- pi-rcmt of rotenone^ with talc a'' a dilue-.t. A-iplic?ti'-^ns of 
the undiluted finely groiond r-'^ot -^f th^ gourd Oucurbita foetidissima H. B, 
K, wer.' not s^^ eff-cti^'-e against the c^^'-cumber bo'"tle as the dust nixtures 
c^ntaininr.; derris, but showed s'^ne possibilities. The derris dust mixture 
was effecti-'-'e for several days and exhibited considerable protection from 
striped cuciimber be-tl^^s for 6 ^nd. 10 (?^ys after a.pplicati"n, even though 
heavy rains occurred and the plants ma-le rapid grovrth. Indications from 
these expTiments were th^t in c^mn.orcial practice the derris-dust mixture 
should bo apnlied evr r'^ f^w dnys . S^ij.fur nitride is n-^t po efff^ctive as 
a dorris-talc-dust mixture containing O.U percent of r-^ti^none. 
The Massachusetts a .Ticulturnl Ex-^'^ri^ient Station (278) in 1938 
reported th^t a spray '^f vretto.ble cube powder cntaining 3*^5 percent 
of roti^n^ne, and \xspd nt thr rate of U poimds in 100 gallons of watT, 
reduced the number of boptles 90 percent, as compnprd with the untreated 
plants, and was the '-lORt effectivp treatment. Cube-clay dust containing 
0.6 percent ^f roten''ne ran'-rd next in effecti^'oneps, vrith an r^5-^"rcent 
reduction in beetle populati^^n. Yield rrcords corresponded with the striped 
beetle control, and the plants treated with cube-clay dust yielded 2.03 
harvoRtpd fr^ut"? per vine, a^ compared vrith 1,;^5 fruit =5 on thp untreatf'-d 
vines. 
