30 



in which case the most destruction comes in seasons when 

 they have a wet spell follow^ed by a dry spell, and then wet 

 gnd dry, when they have sharp changes in the water sup- 

 ply. That is to say, when they have a season which is uni- 

 formly moist they have but little as compared with the 

 seasons in which they have, say, the first part wet and then 

 ^, ery dry and then wet, and so no. The mechanics of the 

 injury I shall not go into. The lesson to be learned, how- 

 ever, which is up to the fruit growers, if that theory is true. 

 is to maintain as uniform a water condition in their soil 

 during the season as possible. That he will do by the or- 

 dinary practices which the horticulturist recommends, first, 

 drainage, because a drained soil is more uniformly wet and 

 more uniformly dry than an unclrained one; cultivation, 

 which conserves the soil moisture and makes it uniform, and 

 the putting on of a cover crop in the middle of the season, 

 which relieves the extra water pressure which may come in 

 the fall from the fall rains ; and spraying the trees. That is 

 not because of the direct results, but because you then have 

 foliage which is green and free from injury throughout the 

 season on account of the uniform removal of the water 

 which comes through the rots. If you start out with a 

 heavy foliage the roots respond with a certain amount of 

 water which they will bring up, with the expectation that 

 this crop of leaves will be there all the season. If that crop 

 of leaves become injured and half of them go off and tho 

 other half is badly injured, you will see at once that the 

 root system will bring in more water than the foliage will 

 be able to get out of the tree. The water that trees use 

 comes in through the roots and goes out through the leaves 

 from day to day. So, the better the foliage the more uni- 

 form movement of the water, so that if the leaves fall off 

 the uneven pressure which is brought about is said to bring 

 about that injury, from too much water. 



The other theory, recently developed in Australia, is 

 that it is arsenical poisoning, due either to spraying or arse- 

 nic in the soil. We Americans do not believe that that is 



