61 



He had found that pure oil could be used with greater safety than the 

 soap emulsion. 



Mr. Scott called attention to what had been said in regard to the 

 scale being more readily killed in the South than in Northern latitudes 

 and thought this must be correct, because Professor Lowe had recorded 

 in his bulletin that he used a strength of 40 per cent crude oil, the 

 highest ever used, but it was effective against the scale, and that 25 

 per cent was absolutely worthless. 



Mr. Felt replied that in the vicinity of Albany Mr. Lowe's results 

 did not hold good, and that 25 per cent.would kill the scales if they 

 were hit. 



Mr. Scott stated that 25 per cent crude oil in Georgia would prac- 

 tically kill every scale with which it came in contact. It had been 

 thoroughly demonstrated with two or three years' experience that 20 

 per cent is all that is necessary. Even 15 per cent crude oil gave 

 good results against the scale and he did not consider it safe to use 

 more than 25 per cent. He was glad that Mr. Marlatt had said what 

 he did concerning the extensiveness of his experiments, as he rather 

 feared that he might be criticised for using such a large number of 

 trees. The Department furnished the oil and the owner furnished 

 the labor, trees, and risk. He stated that there was one orchard in 

 Georgia of 150,000 trees that had been sprayed with the crude oil last 

 winter and another of 200,000, and that, unless one were pretty sure 

 of results, it was too risky to make recommendations. Mr. Scott 

 further stated, in response to an inquiry from Mr. Marlatt, that the 

 crude oil in mechanical mixture was his preference of the different 

 lines of treatment, provided that pumps could be had that would accu- 

 rately discharge the proper amount of oil. Otherwise the soap emul- 

 sion is preferable, 



Mr. Smith inquired if the pumps used were of the new model, to 

 which Mr. Scott replied that the}'^ were of the latest model, that they 

 had been used one day with the oil and water kept separate, but that 

 it became necessary to discard these connections and change to the old 

 style of pump. His reason for preferring the emulsion was because it 

 could be depended upon almost absolutel}'', while with the mechanical 

 mixture the pumps gave varying results. One lead of the hose might 

 be discharging a greater percentage of oil than the other. 



Mr. Scott further stated that he had used the pure crude petroleum 

 in an experimental way the winter before. Twelve trees had been 

 sprayed, of which number 6 were killed. He considered pure crude 

 petroleum quite unsafe, but thought that it could be used as high as 

 50 per cent if applied vary carefully and very lightly. 



Mr. Burgess stated that from the previous discussion it appeared that 

 it must be much more difficult to kill the scale North than farther South. 

 In northern Ohio it was a very difficult matter to kill the scale with- 



