38 MAIXE AGRICULTURAL EXPERIMENT STATION. I906. 



and brown. Alost of the fruit ceased to grow, and by the first 

 of September the larger part of it was on the ground ; though 

 early in the season all the trees were well loaded. The leaves, 

 however, appeared perfectly healthy. 



At the time of harvesting, October 10, most of the trees had 

 lost all of their fruit. Such as remained on some of the trees 

 was, for the most part, small and deformed. Some of the fruit, 

 however, was of medium size with one side cracked as in figure 

 5, and a small portion was without marked blemish. In all cases, 

 however, the texture of the fruit was soft and spongy, — about 

 as might be expected in April or Alay. The surface of the 

 fruits was also characteristic, there being numerous minute 

 elevations or "pimples," corresponding to the grayish dots on 

 the fruit. This feature is shown in figure 5, and was so notice- 

 able that the workmen spoke of it in handling the fruit after 

 removal to the cellar. Though a small portion of the fruit 

 was on the trees at harvest time, it dropped so easily that no 

 attempt was made to save it for packing. The slightest jarring 

 of the limbs would cause it to fall. 



The reason for the condition above indicated is, as already 

 noted, very obscure. A careful microscopic examination was 

 made without finding evidence of any fungous enemy,* even in 

 the brown dry tissue above mentioned. It was then observed 

 that the condition existed only with certain trees included in a 

 fertilizer experiment in which an excess of available nitrogen 

 is applied every year. The first tree noticed was in the plat 

 receiving nitrate of soda and acid phosphate, and later it was 

 found that every tree on this plat, as also on the adjoining plat 

 which received nitrate only, was affected as described. In one 

 or two instances check trees w^hich adjoined the nitrate plat, and 

 received no direct application of fertilizer, showed a tendency 

 in this direction. None of the other trees in the whole orchard, 

 however, gave the least indication of the trouble. A fertilizer 

 plat on which were muriate of potash and acid phosphate, and 

 another on which was muriate only, separated from the first by 

 only a single row of trees, were entirely free from the disease. 



The supposition was therefore made that the trouble was 

 physiological and due to the excessive amount of available 

 nitrogen and the lack of potash. Of course this is a matter of 

 conjecture and can be settled only by definite and careful experi- 

 ment. 



