47 
pump could pnly supply hquid sufficient to fill the lower nozzles. 
This difficulty was overcome by obtaining another pump, so that next 
season we will be prepared at the very outset to put up a good and, I 
hope, a successful fight against this pest, which is costing the nursery- 
men several hundreds of dollars loss annually. 
At Adrian, Minn., Mr. Fred Mohl, proprietor of a large nursery, 
has kindly cooperated with the Entomologist, and has been making 
a series of experiments with the dust spray. Mr. Mohl sprayed 
twice with the “ caustic lime ” mixture, and once with the “ general 
formula.” At the date of my visit, July 12, the trees were looking 
very well, though they were not free from leaf-hoppers. Mr. Mohl 
is of the opinion that, if he had begun earlier, “ before the hoppers 
appeared,” as he expressed it, and sprayed three times, he could have 
kept them well under control. While the writer is quite willing to 
be convinced, he has not absolute confidence in the efficacy of dust 
spraying in this connection. | 
I believe the possibilities foreshadowed in the success of the cart 
as a sprayer are almost unlimited. <A cart to straddle one row and 
spray the straddled row and the two adjoiming rows could be 
easily constructed. These carts, too, including the one we are now 
using, could be made automatic by connecting the pumps with the 
wheels by proper gearing. 
Mr. Smith concurred in the view that kero-water pumps were in 
general unreliable. He hoped that experiments already under way 
on the production of so-called “ soluble petroleum ” would solve the 
difficulty. 
Mr. Slingerland said that in New York they had gone through 
similar experiments for the leaf-hopper on grape vines. With diluted 
kerosene emulsion or whale-oil soap the young hoppers were easily 
killed, but the only way to Ill the adults was to first get them off 
the vines. They were knocked down by a 5 per cent kerosene spray, 
but they would recover from this; consequently 1t was necessary, 
while they were on the ground, to spray again with a 25 per cent 
mixture. 
Mr. Sanderson said that he had failed to find any satisfactory 
form of kero-water pump. 
Mr. Osborn said that he had killed some spectes of hoppers on 
potatoes with 5 per cent emulsion, but it was necessary to keep them 
in the air for this to be effective. 
Mr. Fletcher called attention to the fact that hoppers might often 
be fatally injured even though they appeared all right for a time 
after the spraying, death occurring later. He said that Mr. Lugger 
had killed grasshoppers by dipping one leg in kerosene. 
