I 
- 535 - 
Certain sprays used on onions to control thrips* and maggots 
noticeably lessened the percentage of yellow dwarf infection, es- 
pecially a combination of 1 to 1.5 percent miscible oil in bordeaux 
mixture (4:4:50) with 0.1 percent pyre thrum-soap or nicotine sulphate, 
applied 3 to 5 times at weekly intervals. In some plots the infection 
was reduced from 60 to 2 percent by this spray. 
PELT, E. P., and BROMLEY, S. 17. (2255) 
1932. INSECTICIDES ON SHADE TRESS AND ORNAMENTALS . Jour. Econ. Ent. 
25 (2): 298-304. [Abstract in Rev. A PP 1. Ent. (A) 20: 419-420. 1932.] 
The white pine bark aphid (Ch ermes ( Adelges) pinicorticis Fitch) 
was very satisfactorily controlled with a dormant oil (1:50) to which 
was added 40-percent nicotine sulphate (1:800). A spray of 2 percent 
summer oil plus nicotine sulphate (1:800), and a commercial vegetable 
oil, soap and nicotine sulphate mixture (1:10) gave practically 100 
percent kill of the juniper scale ( Diaspis carueli Targ.) in midsummer. 
Control varying from 95 to 100 percent was secured with 'a number of 
insects by the application of the vegetable oil, soap, and nicotine spray. 
HUTSON, R. (2255) 
1932. TESTS SHOW WAY TO CONTROL RASPBERRY MITES. Mich. Agv. Expt. Sta. 
Quart. Bull. 14 (3): 191-193. [Abstract in Rev. Appl. Ent. (A) 20: 
362. 1932.] 
Besides the oil sprays, other successful sprays were nicotine 
and penetrol, derrisol and soap, and glue. The mites discussed are 
Tetranychus telarius L. , T. mcdanieli McGregor, and Parat e t ranychus ilicis 
McGregor. 
RICHARDSON, H. H. (2257) 
1932. A PRELIMINARY STUDY OF THE I1ISECTICIDAL EFFICIENCY OF THE PYRETHRIN 
NICOTINE AND ROTENONE AGAINST THE GREENHOUSE RED SPIDER MITE. Jour. 
Econ. Ent. 25 (3): 592-599. [Abstract in Rev. Appl. Ent. (a) 20: 519. 
1932.] 
TTith the addition of 0.25 percent potassium oleate soap, rotenone 
at 0.C2 percent is slightly more toxic than the pyrethrins (0.02 percent); 
nicotine is much less toxic than either of these two. Uith sulphonated 
castor oil as the wetting agent, the pyrethrins and rotenone at 0.02 
percent are about equivalent in toxicity; nicotine again is much less 
toxic, about 0.2 percent being necessary to equal the insecticidal 
efficiency of the other two at the concentrations given. Soap is more 
efficient than sulphonated castor oil as a wetting agent for rotenone and 
the pyrethrins. T7ith nicotine, however, the reverse appears to be true. 
Nicotine (1:500) makes distinctly alkaline the almost neutral 0.5 percent 
sulphonated castor oil, but has a relatively slight effect on the already 
alkaline soap solution. 
