_ u _ 
Species of Aleyrod.es are not affected "by derris. — Van der Laan 
(178) in 1936; also de Bussy et al. (^1 ) . 
Etablissements Rotenia in 1932 reported in a letter to R. C. Roark 
that Trial euro dog sp. on tomatoes in hothouses was killed by a proprietary 
dust containing 12 percent of- cube having a 6 percent rotenone content. 
Aphiidae 
Anur aphis cardui (L.), the thistle aphid 
1'eoton (derris extract in fish oil) 112.5 S^- plus twice its weight 
of soar; killed 100 percent. — Institute of Physical and Chemical Research 
( l62 ) in 1927. 
Anur aphis maidi-radicis (Forbes), the corn root aphid 
The South Carolina Agricultural Experiment Station ( 2U9 ) in its 
annual report for 1937 reported that cotton root aphids caused great 
damage in the Coastal Plains area of South Carolina. Three species of 
aphids are usually present. Tamed in the order of their abundance these 
are A. maidi-radicis , Trif idaphis phaseoli (Pass . ) , and Rhopal s i phum sp. 
[probably R. subterrancum Mason] . 
The most practical approach toward controlling these root aphids 
appears to be in mixing some insecticide or repellent with the fertilizer 
and applying the mixture directly to the soil. With this in view, 36 
plots were laid out in each of h fields, and each field, or experiment, 
was treated with 6 different insecticides replicated 6 times. One of the 
insecticides was derris powder (U percent rotenone) applied at the rate 
of SO rounds per acre. Each insecticide was thoroughly mixed with the 
fertilizer and applied to the soil prior to planting. Counts were then 
made of the number of aphid colonies present on 100 linear feet in each 
plot after the cotton came up, also of the total number of plants that 
cane up on 100 linear feet in each plot, and. later of the number that 
were living just before chopping or thinning. The percentage of reduction 
in stand Was then computed, for each treatment. At the end of the fruiting 
period, when all the bolls were set, counts were made of all the bolls 
present on. the two center rows in each plot. ITo significant differences 
between any 01 the treatments appeared in the number of aphid colonies, 
in the percentage reduction in stand., or in the boll counts. So harmful 
or undesirable effects were noted in the growth of the plants -from the 
use of any of the^e insecticides when applied to the soil in the amounts 
stated. 
Tests conducted against the root aphids T. phaseoli , R. subterra - 
neum',.. and. A. naid.i-rad,icis on cotton were reported, in June 193^ "oy Rain- 
water ( 22S ) . In the first series of experiments derris was mixed in the 
soil of the seedbed from 2 to 3 weeks before planting, at the rate of 100 
pounds per acre. Ilhe seed came up to a good stand,. On the derris-treated 
-'-•lot'- 2.5 colonies per 100 row feet were present, in comparison with 7«5 
and. 10.5 is the checks. In another series of tests, conducted in a field. 
where the cotton had been killed. b; r the aphids and it was necessary to 
replant the materials were lightly mixed, with the soil and the seed, was 
