PATHOLOGICAL CONDITIONS 85 



A form of phyllody, known as "false-blossom" or "Wisconsin false- 

 blossom," apparently caused by an excessive water supply has been 

 observed in some of the cranberry bogs of the Northern states. It is 

 characterized by more or less leaf-like calj^x lobes and petals, aborted 

 or malformed pistils and stamens, the production of little or no fruit and 

 an appearance of the plant suggestive of witches' broo'm. The trouble 

 "is usually associated with extreme wet or dry conditions of the bog, 

 but most frequently with an excessive water supply. In most of the 

 localities in which it has been observed the affected plants were growing 

 in a deep, coarse peat soil having an excessive water supply during the 

 greater part of the growing season. "^^° What is evidently a very similar 

 disorder, often caused by disturbed water relations, has been described 

 under the name "virescence" as affecting the coffee tree in Indo-China.^^ 



Chlorosis. — Chlorosis in plants is generally associated with some form 

 of malnutrition and some attention is devoted to it in that connection. 

 However, Taylor and Downing^24 found it accompanying over-irrigation 

 in a number of Idaho apple orchards. Indeed they came to regard it as 

 one of the evidences of excessive applications of irrigation water. It is 

 possible that the chlorotic condition of the trees was induced through 

 some influence of the excess water supply on the plant nutrients in the 

 soil or the foods in the plant, but directly or indirectly the surplus 

 moisture was responsible for it. A chlorotic condition of the peach 

 induced by over-irrigation has been reported in Baluchistan.^" Its early 

 symptoms were much like those of the "peach yellows" of the eastern 

 United States and at one time it was thought to be that disease. It was 

 accompanied often by much gumming and imless promptly treated the 

 tree died. The use of less irrigation water and the employment of cultural 

 practices leading to a better aeration of the soil were efficient correc- 

 tives. Chlorosis has been found in heavily watered seed beds of the 

 western pine in Nebraska while check plots showed none.^' 



Rough Bark or Scaly Bark Disease. — This disease according to 

 Sorauer^'^ results in a scaling off of the bark from the roots and to a less 

 extent from the stem. It has been described as affecting the apple, 

 cherry and plum when growing on low, wet ground. When appearing 

 on the roots it is likely to cause the death of the tree; when it attacks 

 the trunk it is less serious. Histologically what takes place is an excessive 

 lengthening of some of the bark cells. This process may continue deep 

 into the bark layer and interfere with normal functions at the diseased 

 spot. 



Watercore. — Curiously enough it is sometimes difficult to decide 

 whether a certain disturbance is due to drought or to an excess of mois- 

 ture. The temporarj^ rising of the ground water table may result in 

 the death of a considerable part of the root system. Later, with lowering 

 of the water table the soil dries out and if there is a prolonged dry period, 



