OTHER OILS USED AGAINST THE COTTON WORM. 163 



mentsmade by Mr. Schwarz showed that such water does not injure the 

 plant, and when liberally applied was sufficient to kill the very young 

 worms, but had no effect on the larger worms. 



Lutliy & Marx^s insect-powder, — This material, manufactured by 

 Luthy & Marx, Philadelphia, might be mentioned in this connection, 

 because one of its ingredients, judging from the smell of the powder, 

 is tar or some allied substance. A box of the powder was sent by the 

 above-named firm to Selma, Ala., in order that it might be tested for 

 the Cotton Worm, and it was applied in dry form as well as stirred up 

 in water, but had no effect, even on the very young worms. It proved 

 equally harmless to the plant. 



CARBOLIC ACID. 



The fact that this is so commonly used in the South for the ''Screw 

 Worm," and as a general disinfectant, and that it is not yet employed 

 against Aletia, is fair evidence that it has little value in this connec- 

 tion. Our own experience in trying it for other worms is that it has 

 little eft'ect on the worms when made weak enough to be harmless to 

 the plant. Mr. Trelease has experimented with it for the Cotton Worm, 

 and we give here his report to Professor Comstock ; 



September 10, a number of gallons of water, containing from a half teaspoonful to 

 a teaspoonful of carbolic acid per gallon, were applied with a fountain pump. This 

 water was stirred so that the acid was suspended through it as very small globules. 

 It was found to kill some caterpillars, but by no means enough to save the cotton ; 

 and, used in these proportions, it injured the cotton considerably. 



COTTON-SEED OIL. 



Of the various cheap vegetable oils this can be most abundantly and 

 easily obtained in the South, where its manufacture is steadily on the 

 increase. For this reason it recommended itself for experimentation 

 against the Cotton Worm. Like kerosene, it can be emulsified by the 

 aid of milk, but, being heavier than kerosene, the two ingredients mix 

 less readily and separate easier when diluted with water than in the 

 kerosene emulsion. In its action upon the worm it is very similar to 

 kerosene, but a larger proportion of the cotton-seed oil is necessary to 

 kill the average-sized worms, while in its effect upon the plant it is 

 somewhat milder than kerosene. This circumstance renders cotton- 

 seed oil (and, in all probability, all heavy vegetable oils) inferior to 

 kerosene as an insecticide, at least in regard to this Cotton Worm ques- 

 tion, and experiments with it were discontinued as soon as this infe- 

 riority was recognized. It occurred to us that by making a soap by 

 using this oil and the ashes from cotton-seed hulls, which are so gener- 

 ally used for fuel in the manufacture of cotton-seed oil, we might ob- 

 tain a liquid that could be sprayed upon the plant with good effect, 

 thus, on the principle similia similihus curantur, employing the products 

 of the plant itself as an antidote to its worst enemy, these products 



