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TRUCK CROP AND GARDEN INSECTS 
Results with Rotenune Dusts and Sprays 
Results on a-number of tests which have been completed during Septem- 
ber and October on the effectiveness of the rotenone compounds against a 
number of insects are.now available. These results.are distinctly pre- 
“liminary and will possibly, be. auch modified by: additional work, 
ay S. Chamberlin; of the Quincy, Flac). laboratory, reports that 
‘during. the present growing season a small field of tobacco, very’ heavily 
infested with the. garden flea, hopper (Halticus citri Ashn.) was dusted 
with derris. A few rows were treated with straight | derris and the re- 
maincer with cilute material. Applications which totaled nine were con- 
tinued through the greater part of the growing season. No appreciable 
control could be observed. A study of the relatively few serious in- 
festations of this insect on tobacco showed that these invariably fol- 
low culturel practices favorable to the insect curing the late foll and 
winter seasons. Favorable conditions consist of a rank srowth of vegeta- 
tion furnishin a both food and shelter for the insect during the winter. 
These observations. indicate that clean cultivation during the late fall 
furnishes the most see acta seh control remedy for this tobacco pest." 
Mr. Chamberlin also reports the t, of various dusts tested against 
_the tobacco flea beetle (Epitrix parvule Fab.) derris dust produced the 
highest mortality within the shortest period of time. Derris caused an 
.. lumediate and extrene irritation, as.evidenced by the insects! convulsive 
effort following application of the naterial. 
Reports from J. C. Chamberlin, Twin Falls, Idaho, indicate that pre- 
liminary tests show derris to have approximately the same effectiveness 
when used in oil against beet leafhoppers as has pyrethrum of similar con- 
centration. 
Norman Allen, Baton Rouze, La., reports that experiments in which a 
derris dust containing i percent rotenone was used "substantiate previous 
observations that rotenone in additicn to killing the turnip aphid protects 
the turnip plants for several days from attack by chewing insects." Derris 
dust diluted with x-grade tobacco dust to 0.5 percent rotenone and derris 
dust diluted with ground electric sublimed sulphur to 0.5 percent rotenone 
protected plants from leaf-eating species from 6 to 8 days. 
Various results are reported with derris on Murgantia histrionica in 
preliminary trials. J. U. Gilmore, Clarksville, Tenn., reports a field 
test in An Gk derris dust was used, mixed half and half with tobacco dust, 
with entirely wsatisfactory control. G. &. Smith, in work at Baton Rouge, 
La., reports that "as a control for Mursantia histrionica, 1, 2, 3, and 4 
percent rotenoneswere tested in cages in the field. The following respective 
kills were obtained within 144 hours: 71.4, 61.9, 90.4, and 95.2 percent. 
Because the kill obtained with the 2 percent dust was rather low it was 
replicated, giving a 94 percent kill in 144 hours. 
