TWENTY-FIRST ANNUAL MEETING. 215 



what form of plant food they have tried out in Pennsyl- 

 vania and whether they are getting any increase of color 

 through the application of that plant food? 



President Rogers: That is a little out of the line of 

 this discussion. 



Dr. Stewart : I am willing to try and answer that. We 

 are using all of the essential forms of plant food. We are 

 using nitrogen, phosphorus and potash, and besides this, 

 lime and other chemicals suitable to the purpose in various 

 combinations. We have not used basic slag for that pur- 

 pose, but we have used acid phosphate as a carrier, and in 

 neither of these forms has the phosphoric acid shown any 

 effect upon color. We have made one or two experiments, 

 which seem to show some improvement, but that is when 

 it is merged in with the other results, and it has practically 

 disappeared. I am not at all certain that you can mate- 

 rially improve color with any of those forms. An im- 

 proved condition in that line depends primarily on maturity 

 and sunlight. Maturity or sunlight will improve color, and 

 logically anything that detracts from the influence of those 

 elements on the development of the fruit is opposed to the 

 development of color. Sod culture, open pruning, or late 

 picking, and such things, increase color. Opposite conditions 

 decrease it. 



Mr. Pratt: I would like to ask the Doctor whether he 

 has noticed any difference in the size of the fruit when 

 different kinds of sprays have been used. That question 

 was brought up, and I am very much interested in that 

 point, as to whether different kinds of sprays have a ten- 

 dency to decrease the size of the apple. I am a little 

 puzzled on this summer spraying question. It has been 

 intimated that that has a tendency to decrease the size. 

 This year our commercial orchards, as a rule, had very 

 small fruit, and it was not altogether due to the dry 

 weather. 



