- 65- 
In I93U Cory (^iS) led a discu5«=i'n of field results with a.rser.ieal 
suostituteg for the control of ^'egeta'^l-:- ir.sectH. Eep.j.lee, cf I'ew Jersey, 
discussed derris f^r the contr-l ->f the i-lcxican "bern tcetle, ]>arlr;g the 
season nf 195^ ^-^ following matt".rlals were studied: (l) Hone-nixed 
derris dust cntaining 2o pprts of U percent rotrn^ne and 75 parts of talc: . 
(2) derris duet containing 16 parts of ground derris running 5 F^^*^'"'^^^* ^^ 
roten'^ne and 18 percent of t^tnl extractives, 25 parts "f finely"- ground 
dusting sulfur, and 59 parts cf finely ground clay; (3) derris dust contain- 
ing 16 narts of ground derris r^'.ot, running 5 percent of roten-ne and IB 
percent of total extractives, 20 parts "'f Coposil and 6U parts of talc; 
(^) a dust c^nei^ting --f a fine grade rf gypsu". impregnated with derris 
extract in onr.ntitios sufficient to give 0,5 percent ^f rctcn'>ne; (5)" & ^ 
Biiailar dust made "in the sajnc-wayj "ao'.as t-O: e^.rry OiT5 percent" of rotcnona; 
(6) a eimilor du?t mad^ so ae -to -contain 1 .pefccnt .of-'rotcnonov --Bach -Of 
thoso dusts vras u&-3(i-on •ljoans:in l/7-^^e::e "blocks. Two applicr.tions v^<^.e 
made Doforo tho "bcr-riB were .p.ijckod' for market. 
The material «5 made up with ground derris dust were much more effect- 
ive in reducing the feeding injury to folia-;e than ware the materials com- 
posed of impregnated dusts, Tho plants treated vrith gr'iund derris dusts 
showed about 10 percent ^f the foliage eaten at the time the "jeans were 
harvestf^d, whil-- the impregnated m.ateri«ls showed from 30 tr 60 percent r.f 
the folia,:e destr'-yed, A study of the "beetles returning t^ the treated 
blocks showed reinf estr.ti^n -^f the impre^P^ated material treatmrnts first, 
a.nd later the ground-derris-c'ust treatments, Furtherr.ore, . the last 'f the 
gro'.ind-derris-dust materials to be reinfested v;as the dsrris-sulfur-elay 
combination, indicating that this particular derris dust had a mnch greater 
residual effect than any -^f the others. These naterifls were applied by 
means of a two-rev; duster, using metal sir^le-r'-w h'-.ods 6 feet long, 12 
inches vide, and lU inche? high. The use of these hoods m.ade it possible 
t*^ effect satisfactory covrragr and to ^btpin complete kill by the use nf 
10 pounds of dust per acr=, as compared with 25 to 30 pounds per acre when 
applied without the hoods. In view of the fact that the derris dust** were 
8'^ld to the consumer at the rate '^f from IS to 22 cents per pound, the re- 
sultant saving made the use '^f the hoods very attractive. Moreover, the use 
of the hoods made it possible t^^ apply the dust in the presence of consider- 
able wind, instead of ha'^ing t-^ work eprly in the morning or late in the 
evening or at night. These single-row hoods aro describr^d in Circular 711 
of the !Irw Jersey Agricultural Expr-rimrnt Station, — Headlee ( ig^ ) in 1935- 
Crosb • and Chunp (91 ) in 19^^ recommended rotenone dust for u=e 
against the Mexican bean beetle aft^^r the pods have begun to forr^, Bordeaux 
should not be mixed with rcten'-^ne, 
Garman and Turner (161) in I'^^U discussed substitutes f'^r Iced arsenate 
for use in Connecticut on fruits and vcf;eta^les, A dust containing 0,6 
percent of rotenone was recom'^onded for the control of the Mexican bean 
beetle, 
Huckett ( 202 ) in 193^ re-ojrted that during I937 on Long Island dusts 
containing from 0.5 to 1,0 percent of rotenone had been used successfully 
as substitutes for magnesium arsenate for the control of the Mexican bean 
beetle on snap and lima beans vhilo th* ^ods were fTming, 
