244 STATE BOARD OF AGRICULTURE. 



heavy rains can not remove it, such poisons should never be used. Their use 

 is never to be advised either in cases like the currant slug, where the fruit is 

 likely to be used at the same time that we need to use the poison. In case of 

 of the rose slug, too, where the leaves or flowers might bo picked and eaten by 

 children with fatal results, we should always resort to other means. 



Again, some insects like the lice and true bugs do not eat our plants, but 

 insert their beaks through the bark and auy substance exterior to it and secure 

 their food by pumping out the sap. Of course we can never kill such insects 

 by use of Paris green or other similar poison. These difficulties have led me 

 to experiment as I have found time the past few years, in hopes to discover 

 some substance or substances that would be effective in such cases, and free 

 from all objection. 



PYKETHKUM. 



This powder, also known as insect powder, I have found to be one of the 

 substauces which is demanded in this warfare. Pyrethrum is cheap, entirely 

 safe, and, wherever it will destroy, is all that can be desired. As a powder it 

 can easily be blown into our rooms, where it sounds the death knell to the 

 annoying house flies. "What a boon it would have been in pioneer times, 

 before the advent of screen doors and windows, when the gay and festive 

 mosquito called forth, even from worthy lips, epithets more emphatic than 

 refined. 



The past summer I gave this substance a thorough trial, and with great 

 success, on the currant slug, the rose slug, the green cabbage caterpillar, and 

 the zebra caterpillar, the black and yellow striped larva which has been so 

 serious a pest in the cabbage and ruta-baga fields of our State the past season. 

 To use this on outdoor insects, I know of no way more convenient and effect- 

 ual than to mix it with water. I have found that a heaping table spoonful 

 to two gallons of water, about the proper proportion. In applying it is better 

 to force it on by use of a force pump, like the Whitman's fountain pump, 

 which is the most convenient instrument of the kind that I have ever seen, 

 than to sprinkle it on by use of a watering pot. This poison kills, not by 

 being eaten, but by mere contact. It will readily appear that when the liquid 

 is sent on to the plant in a jet it will scatter and touch the devastating insects, 

 when if simply turned on it would fail to reach many, and so could not 

 destroy. I think this accounts for some of the unfavorable reports which we 

 have heard in the use of this valuable specific in battling the "cabbage worms." 



There are two objections to pyrethrum. The first, not a very serious one, is 

 that the active element is somewhat volatile, and so, unless the powder is kept 

 in close vessels, it loses its virtue. To remedy this evil, we have only to keep 

 it in close vessels. Some which I have kept corked in a bottle was as effect- 

 ive this year as when fresh two years ago. 



The more weighty objection is that the powder will not destroy all insects, 

 although S. N. Milco, who sends out fresh and most excellent powder from 

 his extensive plantation at Stockton, California, guarantees that it is univer- 

 sal in its destruction of insects. I find that most true bugs, and many beetles, 

 are not injured by its use. Thus I find that it has no apparent effect on the 

 squash bug, or the tarnished plant bug. 1 have also tried it on several small 

 beetles which attack grain in our storehouses and mills, with no effect, so far 

 as I could observe. I would, therefore, advise the use of pyrethrum in case 

 of all larva that defoliate our plants, when the use of the arsenites is not 



