- 4.6 - 
root for spray purposes, and that sprays wore not so effective as dusts. 
For spray purposes, the nost satisf icto'ry results were obtained with a 
mixture containing 4 pounds of powdered derris root to 100 gallons of water 
in addition to neutral coconut oil soap, penetrol, skin nilk powder as a 
sticker. For dusting, equally satisfactory results were obtained with 
derris and cube mixtures of 0.5 to 1 percent rotenone strength, containing 
talc, clay, or air- floated gyp sun as the silucnt. riot all cabbage worms, 
however, were killed by rotenone-contnining powders, for example the zebra 
caterpillar. Contact dusts containing pyrethron or nicotine were highly 
toxic to this insect if applied in the earl;y stages of larval development. 
The Texas .Agricultural Experiment Station (402) in its 48th annual 
report (published in 1936) reported that derris was considerably more ef- 
fective than cube against the cabbage looper, Autographa brassicac , and the 
larvae of the diamond-back noth, Plutella maculipennis , regardless of the 
carrier used, according to tests conducted at Feslaco and ¥intcrhaven dur- 
ing January 1935. The derris mixtures and the cube mixtures were more ef- 
fective against the larvae of the dianondback moth than against the cab- 
bage looper. Derris- sulphur (15-85) or cube-sulphur (15-85) containing 
0.75 percent rotenone gave better control of cabbage wo-rms than either ar- 
senate of lead or barium fluosilicate on the average in the lower Rio Grange 
Valley, the Winter Garden, or Galveston County. 
The Colorado .Agricultural Experiment Station (87) in 1936 reported 
that during 1934 the insect infestation on cabbage and cauliflower consisted 
largely of the imported cabbage worm. A satisfactory control of these was 
secured with pyre thrum dusts containing 0.18 percent pyrethrins and with 
derris or cube dusts carrying 0.5 percent rotenone. The minimum amount of 
material and the number of applications to give seasonal protection remain 
to be determined. The infestation of the imported cabbage worm was so light 
in 1935 that this part of the work could not be completed. 
The 1935 infestation consisted of the cabbage looper, alfalfa 
looper, and the dianondback moth. These are more difficult to kill. Dusts 
carrying 0.2 percent pyrethrins or 0.75 rotenone, which is higher than 
most recommendations and also higher than the contents of most commercial 
dusts, failed to give satisfactory control. 
The Idaho Agricultural Experiment Station (210) in 1936 reported 
that cube-kaolia dust is effective against several insects. Preliminary 
tests were made with a cube-kaolin dust mixture containing 0.02 percent 
rotenone. This mixture, applied in the center and over the top of ant 
hills, killed most of the colony, and a second application two weeks later 
usually served to exterminate the colony. Occasional light dustings of the 
mixture around shrubbery or ornamentals or at places where the insects 
entered the buildings effectively controlled ants. The dust readily killed 
nymphs of the squash bugs but squash vines soon wore rcinfestcd. One 
thorough d.usting of Virginia creeper killed most of the nymphs and, adults 
of the grape leafhoppcr and a second, dusting 10 days later produced com- 
plete control. Two dustings of the mixture, 10 days apart, controlled the 
grape leaf hopper on grapes. 
