DISEASES AND THEIR REMEDIES. 131 



ease with another, presently to be mentioned. I 

 am convinced that this trouble is occasioned by one 

 general cause the fermenting of sap in the vicinity 

 of the " rot." The sap of the orange abounds in 

 oil and starch, which, in combination with watery 

 particles, favor easy and rapid fermentation, especial- 

 ly when the circulation is slow. So far as I have 

 discovered, this fermentation is induced mainly 

 from two causes first, fermenting manures around 

 the base of the trunk. Of course, this should not 

 be allowed. Second, stagnant water around the 

 roots. If water is allowed to flow or drain slowly 

 from the ground it is not likely to ferment. I 

 have known it to flow for weeks above the surface 

 of the ground with no seeming damage to the trees, 

 but if allowed to stand on the surface, or a little 

 below the surface, under the influence of a powerful 

 sun fermentation speedily sets in, and a few weeks 

 or months thereafter the roots of the tree resting 

 therein begin to show signs of decay. The first 

 symptom is a darkening of the sap, next loosening 

 of the bark of the roots, and last rot of bark. The 

 prevention is, to underdrain, and keep the crown- 

 roots well exposed to air and sunlight. If under- 

 draining is impracticable v carry off the surface water 

 and keep the ground well mulched, that a lower 

 temperature may check the tendency to fermenta- 

 tion. In localities where this disease is troublesome, 

 sour stock, as it is better adapted to wet and acid 

 soils, do better than the sweet stock. 



