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be infested. Corrosive sublimate was the only treatment that gave satis- 
factory control. Only one material, derris, proved very ineffective. 
As it was from the same lot of material that was used the previous year 
with fair results, Brittain assumed that it had deteriorated In storage. 
About two-fifths of a pint of liquid and five-ninths of an ounce of dust 
was applied per plant. In' 1925 Brittain (42) reported that mature larvae 
immersed for 5 seconds in a suspension of derris root (3 lb. to 100 imp. 
gal.) and then placed upc-n their" food plant were unaffected, whereas a 
1: 1,000 solution of mercuric chloride killed 10 percent. 
K. P. Smith ( 254 ) in 1925 reported that a mixture of 1 ounce of derris 
with 2 ounces of soot per square yard did not give results promising enough 
to justify further trials. 
Turner ( 277 ) in 1932 reported that in 1931 rotenone extracted from cube 
was tested for control. Early cabbages and two series of treatments were 
used in the tests.* One series was treated once, on May 1; the other twice, 
on May 1 and May 15. Rotenone was used in three dilutions, and was applied 
in an acetone-water suspension, l/2 cupful being poured around the base of 
each plant. Heads were harvested on July 8 and July 14, and yields were 
compared with those obtained by the use of bichloride of mercury. These 
figures show that rotenone at the rate of 1: 2,500 and 1: 5,000, even in a 
single treatment, increased the yield of cabbage, as compared with the yield 
of check plots. Roteriorie-*at 1: 10,000 was not so effective. The percentage 
of heads maturing in cheCk plots was 72, and on the rotenone plots from 70 
to 100. Comparison : with results obtained with bichloride of mercury shows 
that rotenone was approximately as effective only when u*sed twice at a 
dilution of 1: 2,500. Because of the small size of the rotenone plots these 
results cannot be accepted as final; however, it is evident that rotenone 
has some value in control. - 
' Benkert and Company (25) in 1934 wrote that for the root maggot 
attacking cabbage derris dust, should be applied around the stalk as soon as 
the eggs are found. " . ." . 
Pegonrya hyoscyani (Pahz.)', the spinach leaf miner 
Jancke ( 150 ) in 1931 reported that in experiments with the beet fly, 
a mortality of 80 percent was attained for 4 days with concentrations of 
Polvosol of 1 percent and 1 p. p.m. These results suggest that the spray 
would be of value against the cherry fly ( Rhagoletis cerasi (L.)). 
Pegomya^nigri tarsus (Pall.) 
.-■'■. ^ , >• • • *•! •-■: .:» ■■■ 
According to Etablis semen ts Rptenia in 1938, in a letter to R. C. 
Roark, this pest on begonia was mitigated by a product containing 12 per- 
cent of powdered Lonchocarpus, nicou root and 88 percent of talcum. 
