82 ORANGE CULTURE IN CALIFORNIA. 



orchards in Los Angeles and San Bernardino counties, and be- 

 came convinced that the reason given above is true. They 

 made their report to the Society on this basis. The report was 

 unanimously adopted, after due consideration. The disease is 

 most prevalent where excessive irrigation is practiced ; trees in 

 depressions in which the water stands in pools after irrigation 

 are most affected, and sometimes they are the only affected 

 trees in the orchard. The disease is also more destructive in 

 orchards in which the water is allowed, while irrigating, to come 

 in direct contact with the trunk of the tree. Orchards on high, 

 well-underdrained land, that receive irrigation only when abso- 

 lutely necessary, and that are carefully cultivated after irigation 

 and before the ground shall have had time to bake and crack, 

 are always found free from this disease. The term "gum dis- 

 ease" is, I suppose, a misnomer. Strictly speaking, it is not a dis- 

 ease; it is simply the result of improper treatment of the trees. 



The prevention of this so-called disease consists of putting 

 into practice the ideas advanced above relative to irrigation 

 and cultivation. To prevent the contact of the water with the 

 bark of the trunk of the tree, there should be turned towards 

 the trees, before irrigating, a ridge consisting of two furrows 

 made with a turning plow on each side of the row. It is not 

 necessary to run the plow deep. The space between the rows 

 should be cultivated in such a manner as to leave the trees on 

 the highest ground, with drainage toward the center of the space. 



There is really no cure for trees affected with gum disease^ 

 unless it be in its early stages. The best and only effective plan 

 is to scrape off from the roots and the trunk of the tree, with a 

 sharp knife, all the decayed bark, being careful to scrape the 

 wood clean, that no diseased portion may be left, and then re- 

 turn the soil to the roots and trunk. It may be well to apply a 

 coat of gum shellac to the parts cleaned, to prevent the moisture 

 of the soil for a while from penetrating the exposed wood. If 

 the tree be not too badly affected, new bark will soon cover the 

 affected part, and the tree will be saved. But when the bark is 

 rotten entirely around the trunk, and the disease extends to the 

 roots, it seldom pays to attempt a cure. To remove the tree 

 and plant another in its place is the most profitable plan to pursue. 



