THE EED SPIDEE ON COTTON. 65 



bined mcotine 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 Uttle 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 mvariable failures that have attended the attempts to 

 destroy mites on sweet-pea foliage, 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 slight injury that occasionally 

 occurs to dehcate fohage. 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 Home 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 gaUon 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 Batosburg the flour-paste 

 solution, prepared accorcUng 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 h(»Uyhock and cotton the mortality did not fall b(>l()W 98 per cent 

 and averaged nearly 100 per cent. 



Tliinking to utihzc; only the; efl'ective part of tlie flour, and to sim- 

 plify the pastc-f cooking operation, a mucilaginous s[)ray was nuide by 

 (converting laundry starch into paste and diluting it with Wiiter. 

 "^This was applied to heavily infr'stcd cotton, and all mites thai 



