42 



to dislodge but uot destroy them. Pure powder applied with a bellows 

 quickly dislodged them, but did not kill over 10 per cent. Those not 

 killed soon recovered and crawled back upon the plant. 



On Potato Beetle. 



Used in the field pure it destroyed about 50 per cent, of the larvae, 

 principally younger ones. Adults were not injured though heavily 

 treated, but when confined in breeding cage and thoroughly dusted 

 they were all killed. I am quite sure pyrethrum is not a satisfactory 

 remedy for Potato Beetle where London purple or Paris green can be 

 used with safety. 



On Tomato Worms. 



Several species of Sphingids were quite numerous on the tomato 

 vines, principally quinque-maculata. On these the powder was used 

 pure and also diluted three times. I did not observe an instance where 

 thoroughly applied that it did not j>roduce death in from two to three 

 days. 



On Squash Bugs. _ 



Diabrotica vittata and also 12-punctata were treated with the powder 

 both pure and diluted three times. It destroyed them ver}- effectually, 

 although I am not certain that they could be so successfully treated in 

 the spring when the plants are small and the beetles very active. This 

 treatment was late in the season when they were feeding on pollen in 

 the bloom of squashes. 



On Fall Web-worm. 



Not enough of these could be found for thorough tests, but pure 

 powder used on one colony made them immediately break from the 

 web, fall to the ground, and scatter in all directions, but two days' ob- 

 servation failed to show any dead ones. 



Several times woolly caterpillars were treated both with powder and 

 solution without in any instance producing death. 



The powder used throughout was the rosetim, and from one package. 



Buh acii ( Pyrethrum cineraruefolium ) . 



I was ordered to obtain this powder direct from dealers, and finally 

 sent to Stockton, Cal., for it. It did not arrive in time for full com- 

 parisons with P. roseum, but I tested it quite thoroughly on P. brassier. 



Used in minute particles it kills in one to three hours, was decidedly 

 slower in action than P. roseum, but the weather was cooler. Exposed 

 on leaves of plants it killed up to three days' exposure though very slow 

 at last trial. Weather cool as before mentioned. 



Diluted with flour it kills in small jars up to 30 dilutions, but in 

 cages was not effective after 10 dilutions, and I think most of these 



