APPLE DISEASES 121 



expected to be affected very little in comparison to those which 

 are exposed to the sun. The diseased portion of the fruit is not 

 easy to detect externally, hence the presence of water-core in 

 an apple may not be suspected. However, the experienced 

 observer is sometimes able to detect diseased fruits by their 

 external appearance. Fruits which should be normally green 

 or yellow will show a blush on one side. Red or dark-colored 

 apples do not exhibit such marked external signs of the trouble. 

 On cutting into a water-cored apple, hard, transparent, watery 

 areas are found in the flesh. Such areas are practically always 

 in close connection with the vascular system . The first evidences 

 of water-core are found here. The bundle shows a water-soaked 

 area about it. The lesion may be near the stem or elsewhere in 

 the flesh, since the bundles are scattered. Occasionally these 

 scattered spots may be small, or there may be extensive watery 

 areas near the surface of the fruit, although none extends up to 

 the skin. Affected apples give off a sweetish, fermented odor, 

 and the taste is not unlike that of frozen fruit. In the later 

 stages, liquid is usually found in the seed cavities and the harder 

 inner membrane of the carpels is cracked and covered with 

 hair-like growths, which eventually assume a brownish aspect. 



Cause. 



The presence of excess water in the affected tissues gives the 

 described appearance. But the factors which bring about this 

 excess water in certain regions of the fruit are not thoroughly 

 understood. It seems certain that fungi, bacteria and insects 

 are not concerned in bringing about water-core. It is generally 

 accepted that conditions affecting transpiration are the prime 

 factors inducing water-core. Reduced transpiration results 

 usually in excessive sap-pressure, and water is forced into the 

 spaces between the cells of the fruit, giving the affected area a 

 glassy, transparent appearance. There is no one factor which 

 can bring about water-core ; two or more factors are necessary, 

 and these must favor excessive sap-pressure and reduced tran- 



