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Po\7dersd derris root diluted to a 20-percent concentration with 
calciiM carbonate, as well as the commercial derris dv.sts, gave 
perfect control on the chicken lice I !e nop on "biseriat-um Piaget and 
G-onio cotes gigas Tasch» and the Gyropid lice Gyro pus oval is ITitzsch 
and Gliricola porcelli L, on the guinea pig. 
Xopp (55) in 1924 reviewed the use of derris as an insecticide, 
Derris pov/der has given excellent results against plant lice,, Pucerons 
du Pommier (500 grams to 800 liters of water containing 1 kilogram of 
soap); I.ialacosoma (500 grams to from 32 to 500 liters of water); larvae 
of Kyphantria cunea ; Anisota senatoria (500 grains to 100 liters con- 
tainini;j 250 grans of soap); Datana ministra (500 grams to 200 liters); 
Autographa "brassicae (500 grams to 100 liters containing 250 grams of 
soap); Lygidea mendax ; Heterocordylus m alinus ; Leptinotarsa docenlincat?. 
(500 gratis to from G4 to 500 liters of water), 
MacDougall (60 and 61) in 1924 reported tests with a proprietary- 
preparation of derris. Any scab and matted hair obscuring the exit holc- 
of the larva in the skin was cleared away before the dressing was applied. 
One ounce of dorris to 1 imperial quart of water killed 66 percent, and 
1 ounce to 1 pint killed 94 percent of the warbles. Ho injurious effects 
attended any of the cattle dressed with derris for warble infestation 
and there v/as no discomfort to the hands of the dresser. 
Howard (51) in 1924 reported that the active principle of Chara 
foetido. v;as toxic to mosquito larvae and had been shown by MacGregor in 
2a^lr-tid to be similar in its action to that of derris. 
In 1924 the Minnesota Agricultural Experiment Station (71) 
announced that one of its projects in economic entom.ology 'vas the stud;^'' . 
of derris for the control of external parasites of domesticated animals, 
under the direction of Paul I.I. Gilmer and 0. C. Mc3ride, but no report 
on this project appears to have been made. 
Ilclndoo and Sievers (65) in 1924 published the results of tests 
with 232 preparations from 54 sxjecies of plants against 28 species of 
insects, 
Following are the summarized results, obtained by using a cOiOnercial 
powder, consisting of a mixture of Derris elliptica and D. uliginosa . 
The pov/der, used as a dust, was efficient against three species of 
aphids ( Aphi s sp, A and 3 and liacrosiphoinella sanborni ) , and silkworms, 
but killed only about half of the Macro si phum sp. A tested Tvithin 24 
hours; used as a decoction (No, 110a, not filteredT and also as a hot-water 
extract (ITo, 110b, filtered), it -.vas efficient against Aphi s sp. A and 
3; and used as a fum.igant, it wa.s efficient against Hyzus persicae Sulz,, 
Macro si phum sp. C, silb-vorms, and the lady-beetle tested, but inefficient 
againct v/obworms and small tent caterpillars. 
