AND OTHER INJURIOUS INSFXTS OF I907 AND I908. 23 



trees, necessitating driving the machine in every row. On account 

 of the varying width of the rows, and the irregular growth of the 

 trees of some varieties, a few trees were scraped by the machine, 

 more particularly in the older stock at Owatonna than in the three- 

 year-old stock at the other nursery. Fine Vermorel nozzles were used 

 on both machines, and the spray thrown as much as possible from 

 below, so as to strike the under sides of the leaves. 



Kerosene emulsion in different proportions, fish oil soap, tobacco 

 water and resin wash were the different sprays used in the experi- 

 mental work. At (Dwatonna kerosene emulsion only was used. The 

 other sprays were applied at Albert Lea. 



Kerosene Emulsion: Kerosene emulsion was made after the 

 following formula : 2 gals, of kerosene, 1 gal. of water, and 12 oz. ot 

 Lenox soap. This stock solution was diluted to dififerent proportions. 

 A 5% solution w'as sprayed upon apple stock at the Wedge nursery 

 June 14th, but this strength was found far too weak to be effective, 

 onlv about 10% of the total number of young hoppers being killed by 

 it. On June 17th and 18th a 7>2% solution of emulsion was used. 

 In one case 55% and in another 7S% of the nymphs on the trees were 

 killed. 



A 10% solution of emulsion was used at Albert Lea on the same 

 date, resulting in killing 46% in one case and 61% in another. A 

 10% solution of kerosene emulsion was also used at Owatonna with 

 success. Two sprayings were made, tlie first June 19th, and the second 

 July 18th. The counts which were made at Owatonna showed a 

 higher percentage in the number of nymphs killed than at Albert Lea 

 for the same strength of solution, but so few trees were counted in 

 the Owatonna experiment that the data are not sufficient to base a very 

 definite percentage upon. Very many of the nymphs were in the 

 older stages at this time, and very active, so that counts would be 

 subject to considerable error. 



Fish Oil Soap : Fish oil soap was used at Albert Lea on July 

 17th at the rate of 1 lb. of soap to 10 gals, of water. The soap was 

 first boiled in a large kettle, adding water to assist in dissolving. The 

 heavy soap solution was then poured into a large spray pump, and 

 water added so as to make the proper proportion of 1 lb. soap to 10 

 gals, water. At this time the leaves at the top of the trees were badly 

 curled by the leaf hopper, and the fine spray could not penetrate those 

 curled leaves so as to kill the hoppers within. A large number of 

 nymphs escaped injury on account of being hidden in these curled 

 leaves. Where fairly hit with this spray both adults and nymphs were 



