256 EEPORT UPON COTTON INSECTS. 



against the Eocky Mountain locust, was tried : A quantity of kerosene 

 was put into a pan; all that would flow was then poured out, leaving 

 only a thin film over the bottom of the pan. A dozen cotton- worms were 

 then put into the pan. At the end of two minutes all were dead. But 

 the danger of injury to the cotton-plant, and especially of knocking off 

 the bolls by any machine employed for jarring the worms from the plants 

 into receptacles containing coal-oil, will prevent the use of this substance 

 in this way. 



Pyrethrum. The value as an insecticide of powder made from the dried 

 flo wer-heads of different species of Pyrethrum, and sold under the name of 

 Persian Insect Powder, has long been known, but its expense has pre- 

 vented its general use except for insects infesting houses and parasites 

 upon domestic animals. For the same reason, we neglected to experiment 

 with it on the cotton-worms, believing that, however efficient it might 

 be, its cost would prevent its use against insects infesting field crops. 

 But there has been introduced into California a Dalmatian species of 

 Pyrethrum (Pyrethrum cineraricefolium,) from which a powder equally 

 as good as the imported powder is made. And we have recently learned, 

 what is equally important, that this powder can be produced at a price 

 which will admit of its being used on field crops. The Californian pow 

 der is known as buhach. 



The most important peculiarity of powder made from Pyretlirum is 

 that, although deadly to insects, it is harmless to man and domestic 

 animals. The neglect to experiment with this powder upon the cotton- 

 worms this season is not a serious matter, as it is not yet produced in 

 this country in sufficient quantities to admit of its taking the place of 

 remedies we now have. We understand that arrangements have been 

 made for growing the plants upon a large scale, and before the sub- 

 stance can be put upon the market in large quantities the necessary 

 experiments to determine its efficiency and the best mode of application 

 will have been made.* 



MODES OF APPLYING POISONS. 



Second in importance only to the choosing of the most effectual poison 

 is the adoption of the best mode of applying the remedy. Although 

 many methods have been adopted, they may be classified under two gen- 

 eral heads: First, use of poisons diluted with water; second, use of 

 poisons diluted with some dry substance. 



Before entering upon the discussion of these methods, I wish 'to urge 

 the importance of making early preparations for poisoning. As yet most 

 planters do not seem to realize that fighting the worms is a part of the 

 necessary labor for raising a crop of cotton. As a rule no provision is 

 made for this work in the way of purchase of poison or implements for 

 ics distribution, or conveniencies for getting water, until the worms are 



*The Pyrethrum cineraricpfolium was introduced into California and is raised by Mr. 

 G. N. Milco, of Stockton, CaL 



