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and the leaf-sating weevils P hyllob ius pyri and P. cblongus . 
Kearns and Marsh (235) in 1937 recommended derris or derris extract 
as a spray for the control of the plum sawfly. The wash should contain not 
less than 0.004 -percent crystalline rotenone. The trees should "be sprayed 
about May 10-20 and again 7 days later. Barbasco or any other rotonone- 
containing material may he used as a substitute for derris provided it is 
suitable for use with a white oil emulsion. 
Tor the control of the pear slugworm or sawfly it is stated the 
second brood is "best controlled by the application in mid-July of a wash 
containing 6 ounces of nicotine and l/2 pound of wetter to 100 gallons of 
water, or 1-1/2 pounds of derris or barbasco root (containing not less 
than 1.5 percent rotenone) may be substituted for the nicotine. 
Suitable wetteis are Agral 2, Lethalate letting Preparation, and 
Sulphonat ed. Lcr ol . 
The Agricultural and Horticultural Research Station of the University 
of Bristol, England (47), at Long Ashton in 1937 reported that investiga- 
tions were continued or the chemical .and biological evaluation of rotenone- 
containing material:.-. The work included experiments with the ground root 
and extracts of Peri' is and Lone ho carpu s spp. 
Kearns, Marsh, and Martin (236) in 1937 reported tests made in 
England with combined washes to test the efficacy of spreaders. Tests 
were made with derris, derris extract, and barb^s^o (5.6$ rotenone and 17$ 
ether extractives). 
Potenone-containing insecticides are shown to be suitable for use in 
field trials for the comparison of the relative efficiencies of spray supple- 
ments as penetrants. The synthetic spreaders Agral 2 and sulphonated lorol 
used with rotenone-containing insecticides for the control of apple sawfly 
( Hoplocampa testudinia ) have been proved more effective at 0.05 percent 
than sulphite lye at 0.75 percent,, gamma- sulphonat es at 0.05 percent being 
intermediate in efficiency. The most effective spray supplement examined 
was a refined (grade G-) petroleiim oil emulsified with sulphite lye, the 
superior efficiency of which as a penetrant may have been associated with , 
solubility factors. The grade G- petroleum oil proved more efiective than 
a water- soluble spreader as a supplement for rotenone-containing sprays 
applied for the control of the plum sawfly, Hoplocampa flava . 
In field tests against the tobacco flea beetle, Lp itrix parvula , P. 
on shade-grown tobacco in Florida, Chamberlin (69) found cube dusts 
containing 1 or 1.5 percent rotenone more effective than a cube dust 
containing 0.5 percent rotenone. 
White (464), in a revision of E-376 issued March 1937, gave 
essentially the same information as far as cube is concerned as ir the 
previous edition. 
Dudley, Eronson and Carroll (120) in 1937 reported no difference 
in the "value of derris and cube sprays for the control of the pea aphid. 
