- 19 - 
Brannon (5) in 1°34 reported on the close correlation between tem- 
perature and kilT of the harlequin bug \rith rOtenone sprays. In conducting 
field toxicity tests in 1933 Brannon observed that 20 adults in each treat- 
ment, when sprayed in the field and placed in field cages over sprayed 
plants, yielded the following data: 
Relative : 
Date of treatment : Temperature : hum-' dity : Mortality 
"F Percent Percent 
September 6 81 72 90 
12 83 74 94 
21 68 76 5 
29 76 70 20 
October 4 71 78 25 
At the 1034 meeting of the American Association of Economic Ento- 
mologists, Cory (87) led a discussion of field results Y. r ith arsenical 
substitutes for the control of vegetable insects. Hixson of Oklahoma 
reported that derris dusts and sprays were ineffective. Marcovitch of 
Tennessee reported that a dust composed of 1 part of derr:s and 7 parts of 
talc gave very good control of the harlequin cabbage bug in cage tests. 
Robinson of Alabama reported that derris-talc or derris-sulfur dusts 
(0,5 percent rctenone) gave not over 85-percent kill of the adults. 
Gilbert and Popenoe (31) in 1934 reported that for the harlequin 
bug derris extract, 4 table spoonfuls to 3 gallons of water, with two 
1-inch cubes of soap added, has been found to have some value against 
the young bugs, but the full-grown ones are almost spray-proof. 
T.alker and Anderson (93) in 1934 reported that in cage tests derris 
gave much better results than pyrethrum. Proprietary derris products 
tested included Cubor, Kubatox, and Sprayrite. 
The Alabama Agricultural Experiment Station (l) in 1935 reported 
that derris alone is not very effective but when nixed with sulfur is of 
some value as a repellent, 
Tialker and Anderson (94) in 1935 reported that thoroughly dusting 
harlequin burs with a derris dust containing at least 0.5 percent of 
rctenone usually givesbetter than 75-percent kill. However, sometimes 
the results arc erratic, with the dust failing to give more than 25- 
percent control. The exact cause of all this variation has not been 
determined, but cool, windy weather seems greatly to reduce the effective- 
ness of the dust. This material is not entirely satisfactory, but when 
thoroughly applied it has given better results than any other material 
tested, Pyrethrum dust containing nearly 1 percent of pyrethrins 
paralyzed the bugs to. porarily, but they scon recovered and apparently 
suffered no ill effects. 
A derris-sulfur dust (0,5 percent rotenone) when applied at the rate 
of 35 pounds per acre is ever 90 percent effective. — Fcnton (26) in 1956, 
-^•SSS?*** 
