50 



and there was a gentle breeze. Tree 116, a badly infested Lombard 

 plum, showed serious injury July 3, at which time several limbs were 

 dj^ing and the remainder did not present a normal, vigorous appear- 

 ance. August 9 the tree was dead and all the leaves thrown out in 

 the spring had shriveled. Tree 117, a very badlj' infested Crawford 

 peach, was also sprayed at the same time, and July 3 it was dead. 



It might be added that the oil was used liberally, and that in the 

 case of tree 117 the infestation was so very bad that it was hardly 

 expected that the tree would survive. 



Some comparative exxDeriments with mechanical crude petroleum 

 emulsions were made. The above-described oil from Titusville and 

 an oil used in the experiments last year were tried. The latter was 

 purchased in the Albany market as crude petroleum sold by the 

 Standard Oil Com]3any. It is a quite fluid greenish oil, and that used 

 in 1901 gave a reading in the field of 11.8° Beaume. Neither the 20 

 nor 25 per cent emulsions of either oil injured the trees, so far as 

 could be seen, this agreeing with the results obtained with the emul- 

 sions of Standard oil in 1900. The Standard oil, that is the heavier 

 one, appeared to be a little more effective as an insecticide, but as the 

 lighter Titusville oil has been used in 25 to 50 per cent emulsions 

 without injuring the trees and with verj' satisfactory results as an 

 insecticide, it would appear that the heavier the oil the less can be 

 used with safety and the more effective it is as an insecticide. There 

 is evidently a very narrow margin between the amount of this sub- 

 stance necessar}^ for satisfactory work against scale insects and that 

 which will seriously injure or kill trees, especially peach and plum 

 trees, and in the case of those verj badly infested, particular^ if the 

 bark is quite rough, it is doubtful if enough oil can be applied to 

 kill practically all the insects and at the same time not injure the tree 

 seriously. 



The experiments tried last year with a combination of 1 pound of 

 whale-oil soap to 1 gallons of water, to which was added 10 per cent 

 crude petroleum, were not quite satisfactory, as it was hoped that the 

 combination would prove more effective as an insecticide and less 

 injurious to the trees than either substance separately in the usual 

 proportions. This year both 10 and 15 per cent of the crude iDetroleum 

 obtained from the Standard Oil Company Avere used in combination 

 with the pound to 1 gallons solution of whale-oil soap. Tliere was no 

 perceptible injury to the trees in either case, and the San Jose scale 

 was pretty thoroughly checked with botli mixtures, the one Avith the 

 higher per cent of oil giving on the whole the best satisfaction. 



The results obtained with whale-oil soap solutions, both li and 2 

 pounds to the gallon, were up to date practically the same as those of 

 last year. The scale was severely checked, but in no instance was it 

 so thorough as where crude petroleum in some form was used. Two 

 pounds to the gallon gave a little better result than the weaker 

 solution. 



