64 BULLETIiSr 416, U. g. DEPAETMENT OF AGRICULTURE. 



of sulphur dust. We can state that this treatment (except for such 

 verj^ prostrate plants as violets) is not at all effective in the Southeast. 



Sulphur mixed with water was sprayed on infested cotton. Exam- 

 ination showed that the red spiders were in no way affected. When 

 soft soap was added to this same spray, however, the resulting mor- 

 taUty was from 50 to 99 per cent, depending on the thoroughness 

 with which the preparation was kept mixed. 



Potassium sulphid has been tested at strengths of from 4 ounces to 

 3 gallons of water to 1 ounce to 4 gallons of water on cotton, sweet 

 peas, hollyhock, beans, and violet. The former concentration shghtly 

 damaged the fohage and a mixture of 1 ounce to 2 gallons of water 

 was found to be ideal. This spray commends itself from every view- 

 point — cheapness, simplicity of preparation, ability to kill quickly, 

 and safety to foliage. 



Both homemade and commercial lime-sulphur sprays were carefully 

 tested on cotton, beans, and sweet peas. The mortality on cotton 

 and beans was practically complete, but the results on infested sweet 

 peas were invariably unsatisfactory. With the addition of neither 

 flour paste nor gelatin was this substance effective on sweet-pea fohage. 

 This is quite in agreement with Parker's results, and is explainable 

 through the fact that the pubescent surface of the sweet-pea leaf pre- 

 vents the even spreading of the insecticide. On cotton, beans, and 

 several other hosts lime-sulphur is a perfect red-spider spray. 



Sodium sulphid was tried repeatedly on infested cotton and beans. 

 The greatest mortahty obtained against red spiders on beans, a host 

 AveU adapted to red-spider spraying, was 58 per cent, and the prepa- 

 ration was so strong as to damage the leaves somewhat. The addi- 

 tion of fish glue resulted in a mortahty of 95 per cent, but in this 

 case it is believed that much of the destruction was caused by the 

 mechanical action of the glue. 



Nicotine Preparations. 



Nicotine sulphate and fish-oil soap or miscihle oil. — Nicotine sulphate 

 used by itself is very unsatisfactory as a red-spider spray. This prep- 

 aration was tested at strengths of from 1 : 400 to 1 : 800 against red 

 spiders on cotton, beans, sweet peas, and violets. The best results 

 were secured on infested cotton, using the extract 1 : 640, a mortality 

 of 70 per cent being obtained. When combined with fish-oil soap 

 Cone-half ounce nicotine sulphate, one-fourth pound fish-oil soap, 2 

 gallons water) its effectiveness was perfect. 



The mixture of nicotine sulphate (1 to 500) and a miscible oil 

 (1 to 40) also gave complete mortality. The addition of flour paste 

 had almost no noticeable effect in increasing the percentage of mor- 

 tahty. We believe, in the case of the excellent results obtained from 

 the use of combined nicotine sulphate and fish-oil soap, and of com- 



