54 



stated that from what he had seen of the effects of pure kerosene upon 

 fruit trees, he would advise the fruit growers, especially of Maryland, 

 to avoid the use of mineral oils. He said Captain Emory, one of Mary- 

 land's largest and most successful fruit growers, had been persuaded to 

 spray his Buffum aud Duchess pear orchards with pure kerosene upon 

 recommendations made in Bulletin No. 125 of the New Jersey Experi 

 ment Station, which he received in January, 1898. Captain Emory 

 asked his (Mr. Johnson's) opinion regarding this treatment, aud was 

 strongly urged by him not to spray the entire block, but to limit his 

 experiments to a half dozen trees and see the results, and be his own 

 judge as to the efficiency of this method for the destruction of the San 

 Jose scale. Instead of using a few trees, as advised, 132 trees were 

 sprayed, and the results were so conspicuous he was of the opinion that 

 this ocular demonstration [presented photographs] ought to be sufficient 

 for the most skeptical. Captain Emory assured him that if it had not 

 been for his appeals to him not to spray with kerosene, he would have 

 killed his entire orchard, and thus lost several thousand dollars in fruit, 

 as the trees not sprayed were this year laden. He said it was needless 

 for him to say that this experience was sufficient for one of Maryland's 

 most enterprising fruit growers, and that Mr. Emory was now thoroughly 

 convinced that pure kerosene sprayed during the " middle of a sunshiny 

 day," in the "finest possible mist," in the hands of an expert, is surer 

 death to certain trees than the San Jose scale. 



Mr. Johnson also called attention to the reference Dr. Smith had 

 made in his report for 1897, to the pear trees he had sprayed with pure 

 kerosene September 30, on Captain Emory's place. Dr. Smith had seen 

 these trees about fifteen days after they had been sprayed, and reported 

 that they were none the worse for the treatment. Such a report was 

 misleading. While it was true that the foliage and the tree, so far as 

 it looked in the fall, was not seriously injured, nearly all the fruit buds 

 had been killed. The tree sprayed in the morning had only 7 pears, 

 the one treated at midday 11, and the one in the evening 17, while 

 those surrounding, sprayed with whale-oil soap and fumigated with 

 hydrocyanic acid gas, were laden with fruit. The pears on two trees 

 were counted; one contained 214 and the other 197. These pears were 

 extra fine Bartletts and were valued at one half a cent each. The 

 fruit, therefore, on one tree was worth $1.07, while the other was esti- 

 mated at 98 cents. The difference between the value of the fruits 

 upon those sprayed with kerosene and those sprayed with whale oil 

 soap or fumigated was enough to have purchased the soap or cyanide 

 for 25 trees. Mr. Johnson, who had with him photographs of these 

 trees, said he did not think it good policy to report upon such experi- 

 ments too soon, as such statements were very often misleading. He 

 did not see any advantage in using pure kerosene anyway if 50 per 

 cent kerosene and water would destroy the scale. He said he was 

 now using kerosene diluted one-half with water in Maryland as a sum- 



