THE RED SPIDER ON COTTON. 65 
| pined nicotine sulphate and a miscible oil, that the efficacy was 
| derived principally from the soap and the oil rather than from the 
nicotine ingredient. The nicotine sulphate applied by itself dries on 
the foliage in little beads so that the mites in the interstices are not 
affected. 
OILs. 
A commercial miscible oil preparation was tested against red spi- 
ders on cotton. It was found that a strength of 1 to 20, and even 
as weak as 1 to 30, sufficed to kill all red spiders, and no injury to 
foliage resulted. The spray is easily prepared and spreads fairly 
well over the infested leaves. 
An oil that is easily miscible with water is more caustic than the 
foregoing composition and should not be employed stronger than a 
dilution of 1 to 32. This miscible oil induced complete mortality to 
red spiders on cotton, beans, and sweet peas. When one considers 
the almost invariable failures that have attended the attempts to 
_ destroy mites on sweet-pea fohage, an idea of the effectiveness of this 
preparation may be gained. Its spreading qualities are excellent. 
When not less than 2 gallons of kerosene were used to 12 gallons 
of water in making kerosene emulsion the mortality of mites on cot- 
ton and beans was complete. The spreading property of this spray 
is excellent. The only possible arguments against its employment 
are the labor of preparation and the shght injury that occasionally 
occurs to delicate foliage. A weak solution of kerosene emulsion, 
when fortified with a small amount of a miscible oil,.did not give 
satisfactory results. 
ADHESIVE SPRAYS. 
In 1903 Volck experimented with flour paste as a spreader for 
lime-sulphur solution. The success of this additional ingredient, 
perhaps, may have suggested to Cook and Horne the value of paste 
alone, for in 1908 they recommended the latter against the red spider. 
Again, in 1913, Parker determined that a flour paste (cooked), con- 
sisting of 1 pound of flour to 1 gallon of water, when diluted at the 
rate of 1 part paste to 9 parts water, produced complete mortality 
to red spiders on hops in California. At Batesburg the flour-paste 
solution, prepared according to Parker’s formula, has been carefully 
tested on sweet peas, violets, beans, hollyhock, and cotton. On 
sweet peas, violets, and beans the results were unsatisfactory, while 
on hollyhock and cotton the mortality did not fall below 98 per cent 
and averaged nearly 100 per cent. 
Thinking to utilize only the effective part of the flour, and to sim- 
plify the paste-cooking operation, a mucilaginous spray was made by 
converting laundry starch into paste and diluting it with water. 
This was applied to heavily infested cotton, and all mites that 
