- 540 - 
Spraying with nicotine sulphate is recommended, as for Aphi s 
pom i or A. m alif oliae . Should a second application be necessary, it 
may "be made just "before the "blossoms open so as also to "be useful 
against the green apple bug (tygus communi s var. novascotiensi s Knight). 
A number of contact dusts were also tested for comparison with 
the liquid spray. Nicotine sulphate was the basis of these dusts, 
this material being mixed and dried and ground with kaolin, yellow clay, 
or sulphur at the rate of 2 lb. to the 100. The formulas for the 
first of these was obtained from R. E. Smith of California. Tobacco 
dust was also tried as well as free nicotine with sulphur. None of 
the dust mixtures gave results comparable to the liquid spray. 
HODGSON, R. TJ. (2275) 
1919. FIGHTING THE 'UALNUT APHIS. Calif. Cult. 53 (3): 53, illus. 
[Abstract in Rev. Appl. Ent. (A) 8: 130. 1920.] 
A mixture of 74 percent kaolin and 24 percent hydrated lime 
upon which 2 percent nicotine sulphate has been sprayed kills 95 
percent of the walnut aphid (Ch ro ma-phis .luglandicola ) when blown 
upon the trees by a dust sprayer at the rate of 2 to 3 lb. per tree. 
SMITH, R. E. (2276) 
1919. DUSTING FOR THE 17ALNUT APHIS. Calif. Agr. Expt. Sta. Eept. 
1318-1919, p. 44. 
The essential idea in making the material for this purpose 
consists in impregnating a solid material or carrier with a solution 
of nicotine, followed by the necessary drying and pulverizing. At 
present the following method is used: A mixture of 75 percent kaolin 
and 25 percent hydrated lime is made in a mechanical mixer, and while 
these materials are being mixed the desired amount of Black Leaf 40 is 
blown into the mass in a. fine spray, without any dilution. For the 
walnut aphid a mixture containing about 2,5 percent of Black Leaf 40 
(1 percent nicotine) is being used. Much greater strengths can be 
made and other materials such as sulphate, lead arsenate,' and copper 
sulphate may be added. The dust is applied to the treos with largc- 
power-driven blowing machines made for the purpose. 
ANONYMOUS (2277) 
1922. PLANT PATHOLOGY. Calif. Agr. Expt. Sta. Rep W pp. 118-124, 
132-134, 135-138, illus. [Abstract in Expt. Sta. Rec. 48: 541-542, 
1923.] 
"Notes are given by R. E. Smith on the improvement of Nicodust 
which is said to be becoming quite extensively used in California." 
