Vol. Ill, Xos. 7 and 8.] INSECT LIFE. [Issued April, 1§91. 



SPECIAL NOTES. 



Some new Insecticides.' — Mr. G. C. Davis, who has been acting as spe- 

 cial agent of the Arkansas Experiment Station during the absence, 

 through illness, of the entomologist, Mr. C. W. Woodworth, reports 

 upon the action of some new insecticides on the Cotton Worm in Bulle- 

 tin So. 15 of that station. The substances experimented with were : 

 Petroleum sludge, a kerosene extract of pyrethrum. Santonin, oxalic 

 acid, benzoic acid, mercuric chloride, tartar emetic, salicylic acid, cin- 

 chonin, bi-chromate of potash, hellebore, lead acetate, and veratrin. 

 All of these substances except the first two were applied in powder in 

 the proportion of from one-fourth ounce to 8 ounces of the insecticide to 

 1 pound of flour, and none of them proved satisfactory except the vera- 

 trin which acts both externally and internally and which, although used 

 in the proportion of one-fourth pound to 1 pound of flour, proved nearly 

 if not entirely equal to Paris Green, costing about the same. 



The most important conclusion of the bulletin is, however, the effi- 

 cacy of the kerosene extract of pyrethrum, which the author states 

 "from present indications seems to be one of the most efficacious and 

 at the same time inexpensive and harmless remedies that we have." 

 The proportions were 2J pounds of pyrethrum to IJ gallons of kerosene, 

 which is then emulsified with soap and water. One part of the resultant 

 emulsion to 450 or 500 parts of water is said to be effectual. At a 

 strength of from 500 to 900 parts of water to one of the emulsion, the 

 half grown and smaller worms " seldom escape death." The applica- 

 tion of 1 part to 500 of wat er causes the worms to die in from 12 hours 

 to 2 days according to size. This mixture will kill pupae when any 

 opening in the loose cocoon allows them to become wet. It is an ex- 

 tremely cheap mixture, and according to the formula given by Mr. 

 Davis, cotton fields can be sprayed at an expense of 5 cents per acre 

 for material. 



"* Some new insecticides and their effect on cotton worms. Agricnltural Experiment 

 Station, Fayetteville, Ark. Bulletin No. 15, December, 1S90. 



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