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To prepare a dust containing 1 percent of rotenone, use the following 
formula: 
Derris powder (4 percent rotenone) 25 lbs. (1 part by weight) 
Diluent 75 lbs. (3 parts by weight) 
To prepare a dust containing 0.5 percent of rotenone, use the follow- 
ing formula: 
Derris powder (4 percent rotenone) 12£ lbs. (1 part by weight) 
Diluent 87£ lbs. (7 parts by weight) 
If the rotenone content of the derris powder is greater or less than 
4 percent, the proportions of inert diluent must be varied accordingly. For 
example, a derris powder containing 5 percent of rotenone should be mixed with 
4 parts of the diluent by weight, that is, 20 pounds of the derris powder 
containing 5 percent of rotenone and 80 pounds of the diluent, to obtain a 
1-percent rotenone dust. 
Derris dusts have also given an indication that they may aid in the 
control of certain aphids, as well as flea beetles which infest cabbage and 
related crops. 
Der ris spra ys . — Good control has been obtained with derris root powder 
(containing 4 percent of rotenone) in water at the rate of 2 to 2-g- pounds per 
50 gallons of water, giving a rotenone content in the spray ranging from 0.02 
to 0.025 percent. If the rotenone content of the derris powder is greater or 
less than 4 percent, the amount of the powder used should be varied accordingly 
in order to give the above indicated strengths of 0.02 to 0.025 percent rotenone 
content in the spray. For example, if the derris root powder contains 5.5 per- 
cent rotenone, 1£ pounds of the powder should be used to give the desired con- 
tent in the spray. Under some conditions it may be necessary to add a nonal- 
kaline spreader or sticker to the spray, such as high-grade liquid or powdered 
neutral coconut oil soap, miscible pine oil, or one of the sulphonated oils. 
Pyre thrum 
F yrethrum dusts ■ — Pure fresh pyrethrum dust, containing approximately 
0.9 percent total pyrethrins, diluted with 2 to 3 parts of the same diluents, by 
weight, as recommended for use with derris dust, have shown promising results. 
For the most effective results it is essential that applications of this ma- 
terial should be made late in the afternoon or early in the evening . 
Pyre th rum spra ys . — Fairly satisfactory results have been obtained by 
the use of commercial pyrethrum extracts. These extracts vary as to their 
pyrethrin content. The directions given by the manufacturer should be used 
as a basis for the dilution of these materials. 
Pyrethrum-derris extracts in combination 
Fairly satisfactory results have been obtained with commercially pre- 
pared extracts of pyrethrum and derris in combination. The directions given by 
the manufacturer should be used as a basis for the dilution of these materials. 
