-49ct- 
Derris-kaolin gave results similar to those obtained with cube-kaoli 
Gentner in 1934 tested the same mixtures at Talent, Oreg., against codlin 
moth infesting 25-year-old Bartlett pear trees. Four cover sprays of the 
material tested were applied following a calyx and first cover of lead 
arsenate, and 6 cover sprays of cube-kaolin were applied also following ai 
calyx and first cover of .lead arsenate. Because of delay in receiving 
materials, nicotine-bentonite (o pounds per 100 gallons) was used in the 
third cover spray in place of cube-kaolin, .Then lead arsenate only vas 
used, 5.6 percent of the fruit Was worcnyj when cube-kaolin was vised as 
described, 14.2 percent was wormy; and when derris-kaolin was used, 16.3 
percent was wormyo None of the sprays injured the fruit, but the heavy 
residue of cube-kaolin prevented uniform coloring of pears that developed 
a red cheek. An acid wash containing 3 percent of acid at 100° F. failed 
to remove. a derris-kaolin residue on Dears, but Robinson removed all 
traces of the residue by washing in a solution of sodium silicate. 
Haegele in 1935 tested these mixtures at Parma, Idaho, us ins either 5 or 
10 pounds of the mixture per 100 gallons of water, and making 8 or 12 
applications to trees about 20 years old. Comparative figures for this 
mixture and lead arsenate, 3 pounds per 100 gallons, applied in the regu- 
lar schedule (8 applications) are as follows: 
Material 
i' ru- 
Woi'my 
Free f i om worms 
and stings 
Lead arsenate, 3 pounds 
per 100 gallons, 8 
applications 
Cube mixture, 10 pounds 
per 100 gallons, 12 
applications 
Lead arsenate, 3 pounds 
per 100 gallons, 8 
applications 
Cube mixture, 5 pounds 
per 100 gallons +0.5 
percent of white oil, 
12 applications 
Percent 
68.0 
98.6 
Percent 
2.6 
1.0 
66.3 
91.3 
2.4 
1.6 
"forms per 
100 apples 
N umber 
266.9 
481.9 
181.6 
304.9 
Stings pc 
100 apple 
N umber 
317.3 
16.9 
318.2 
131.8 
Although a heavy residue of cube-kaolin was left on the fruits, this 
did not inhibit coloring. The derris and cube dusts tended to bo some- 
what nauseating to the operators. Derris-kaolin was not so effective as 
the cube-kaolin mixture. 
') in 1935 also reported that derris, 10 pounds per 100 
gallGjas all id also plus 0.5 percent of oil, proved most unsatisfac- 
tory in controlling the insect at Parma, Idaho, in 1934. 
