THE ANNUAL MEETING. 137 



that attack the roots of our cultivated plants. We must remember that this 

 liquid is very volatile, and the vapor very explosive. 



PYRETHRUM. 



This substance has long been in the market under the name of Persian and 

 Dalmatian insect powder, and sold as a destroyer of house flies, cockroaches, 

 etc. But owing doubtless to the fact that the effective element is a volatile oil, 

 the foreign substance often failed to destroy, as it did in my hands. The 

 essential element had escaped. 



In 1879 Mr. Win. Saunders of Ontario experimented with the Persian in- 

 sect powder, the pulverized flowers of Pyrethrum carneum, and P. roseum, 

 and the Dalmatian, the powdered flowers of P. cineraricefolium. He found 

 the latter the most efficient. It only kills by coming in contact, and seems to 

 paralyze the insect at first and finally kills outright. Mr. Saunders experi- 

 mented with house flies, blue bottle flies, grasshoppers, plant lice, etc. He 

 found that all fell upon their backs in from two minutes to six or eight min- 

 utes. The insects remain paralyzed sometimes for two or three days before 

 they die, and a few were seen to recover so far as to walk or fly away. 



Prof. 0. V. Riley has attacked this problem with the characteristic energy 

 with which he grapples any insect question. His experiments show that this 

 substance is equally effective against nearly if not quite all our insect foes. 

 Prof. Riley commenced his investigations in 1878, and has continued them to 

 the present time. During the past season he has pushed his investigations with 

 extraordinary vigor. He has found that mixing the pyrethrum with flour in 

 the proportion of one of the pyrethrum to twenty parts of flour in no way 

 injures the value of the application. And that when mixed with water, at the 

 rate of one tablespoonful to one gallon of water, or even two gallons of water, 

 it still is potent to destroy. 



The great argument in favor of pyrethrum is its harmless nature as effecting 

 man and other animals of the mammalian branch. When breathed it is no 

 more disagreeable than any vegetable dust, and I fed it to a neighbor's dog 

 and regret to state that the dog is still alive and can bark at all hours. 



Heretofore the cost of pyrethrum has been a bar to its general use. It has 

 been sold at $1.25 per lb. But Mr. Milco of Stockton, California, who has for 

 the last few years grown this plant very successfully, has informed Prof. Riley 

 that he has grown 147 lbs. to the acre, and that the whole expense of putting 

 it on to the market need not exceed six or seven cents. When its culture be. 

 comes common, then, we may expect that the price will not exceed that of 

 London purple. Mr. Milco grows the P. cinerarimfolium, and so manufac- 

 tures the Dalmatian powder under the name of " Buhaeh." It is probably true 

 that this plant can be grown in the southern States, and very probably in all 

 sections of the United States; if so we may expect very soon to find it in the 

 market at rates within the reach of all. 



During the past season I have tried this pyrethrum ("Buhaeh"), which I 

 received through the kindness of Prof. Riley, on the larvae and imagos of tho 

 potato beetle, Doryphora lo-lineata on the cabbage caterpillar, Pieris rapcB on 

 squash bugs, Coreus tridis on plant lice, on house flies, and on mosquitoes, and 

 found it speedy death to all except the squash bugs, which even lived in tho 

 ,powder for three days before dying. I also found that one tablespoonful of 

 the powder to forty of flour was effective in killing the cabbage caterpillar, 

 .and that the same amount of powder to two gallons of water was even better, 



