- - 6i - 
Dor'ri.s- sulfur dust (O.5 percent of rotrnono) is of some value for 
comtr.ting floa 'boctlcs on crbbr.go. — Alabojna Pol:^tecimic Institute (8) in 
1935. 
Howard, Mason, and Davidson C_200) in 1935 reported that a hotbed 
of egfjplant heavily infested with flea beetles was cleaned up by spraying 
with ? commercial product composed of finely ground derris root mixed with 
a high-grade soap powder. Derris root should not be mixed with soap if 
residual or lasting effect is desired. 
. The Kentucky Agricultural E:rpcri:nont Station ( 2U6 ) in I935 reported 
talc to be sup -rior to fuller's earth, bcntonite, or tripoli as a diluent 
for derris used to control flea beetles. 
Miles (28^) in 1935 reported that two substances v.'ere found effective 
against floa beetles on Brassicae in England. As soon as the seedlings arc 
breaking through the soil, the rows should be dusted with either naphthalene 
or derris at the rate of 30 to Uo pounds per acre. It can be applied by means 
of a kn.apsack duster, and under ordinary circumstances tvro men can dust an acre 
in an hour ?Jid a half. Two or three dustings may be necessary. Wliile naphtha- 
lene is only repellent in its action, derris dust is definitely toxic to the 
beetles and also repellent. 
Derris vras effective in field demonptrr-tions against fle;^ beetles,-- 
Few Jersey Agriculturrl Exrperinent Stotion (296) in 1935* 
A mixture of 2,5 p^rts of derris, 7o parts of sabadilla seods, and 
90 Darts of talcum -orovcd useful in exterminatin;:;' fler, beetles. — Schotte and 
Gornitz {^ in 1935. 
The Ep.st Hailing Research Station, England (llO) in 1936 stated that 
a proprictrry derris powder was used in the routine spraying program in 1935 
for the control of flea beetles on hops. 
Petherbridge and Thomas ( 31g ) in 193^ reported the results of further 
tests v.'ith derris in England. In 1935> tests vrere made at three places in 
Bedfordshire vrith throe dusts for the control of flea beetles in Brassicae 
seedbeds. The dusts were (l) Derris dust (rotenohe =0,2 percent); (2) 
naphthalono-silic;. (50:50), f^^id (3) a German proprietary dust consisting of 
finely powdered qur.rtz [Haaki?]. Dusts 1 and 2 were applied r.t the rate of 
65 to S5 pounds per acre and Dust 3 ^"t the rate of 1U5 pounds per acre. Both 
Dusts 1 and 2 gav.- very good control of flea beetles. As a result of those 
tests, the authors recommend dusting with a. derris or naphthalene-silica 
dust p.s the plants are coming through the ground rnd subsequently dusting 
at intervals, depending on the weather and the extent of attnck. 
Steer (J^O) in I936 wrote thrt for flea beetles on hops and crucif- 
erous crops derris dust is the preferred insecticide. 
The United St--tes Dep.-rtmont of Agriculture ( 38l ) in I930 referred 
to derris rnd cube ,• s effective against flea be.?tlef destructive to grov.-ing 
tobacco . 
