APPLE DISEASES 



477 



Ripe Hot 



Sclerotiitia fnictigitta 

 See Brown Rot. 

 Root BLicmT. See Blight under Pear. 



ROSETTE 



Rosette has doubtless existed for ages, 

 and has affected many kinds of forest 

 trees, shrubs, plants, and fruit trees. 

 This seems a reasonable inference, from 

 the fact that the causes have existed for 

 ages and the results would naturally fol- 

 low. It is only in recent years, however, 

 since fruit growing for commercial pur- 

 poses has become general, and since it is 

 being studied with scientific accuracy, that 

 rosette has been observed, and become 

 a subject of considerable controversy. 



When first observed, it was supposed to 

 be confined to the arid regions, where 

 the soil was largely a volcanic ash, or dis- 

 integrated basalt, and where the sun was 

 hot enough and the air dry enough to 

 cause a rapid evaporation from the leaf. 

 This theory is now abandoned by those 

 who have carefully studied the subject, 

 and it is known that the disease exists 

 in the humid regions of many countries 

 as well as in the arid regions, although 

 it is conceded to be more prevalent in 

 arid than in humid regions. It is known 

 too, that the disease is not confined to 

 one species of trees, or even to fruit 

 trees, but that ash, willow, walnut, elm, 

 oak, and many other varieties of trees 

 are affected by it. In the arid regions 

 of the Pacific coast states, the disease 

 became so prevalent, where it was gen- 

 erally known as "Apple Rosette," that I 

 determined, if possible, to find the cause 

 and the cure. I therefore began investi- 

 gations, first in my own orchard, extended 

 my observations to other orchards in our 

 community, later to other communities. 

 and later still to other states. Soon after 

 beginning my investigations, I wrote fifty 

 letters to practical orchardists, fruit in- 

 spectors, and professors in our state insti- 

 tutions, to get, if possible, their many 

 viewpoints, and to see if there were any 

 general agreement, or clearly defined con- 

 sensus of opinion on the subject. The 

 answers to these letters were very in- 



structive, but showed wide differences of 

 opinion as to causes. 



My own observations were about as 

 conflicting as the replies to my letters; 

 for often when I had discovered what 

 seemed to be the cause, I found rosette 

 existing under conditions where the sup- 

 posed cause was not apparent. However, 

 I have kept up my investigations and 

 with this disease in mind have visited 

 many of the orchard sections in Wash- 

 ington, Oregon, California. Idaho, Mon- 

 tana, Utah, Colorado, and Texas. 



The Causes Assigned 



I have given here a list of the causes 

 assigned for rosette, and in another place 

 in this article have quoted more fully 

 from the authors, using this as a mere 

 catalogue selected from the replies, as 

 follows: 



Too much water. 



Not enough water. 



Too much alkali. 



An unbalanced food ration. 



Too much barn yard manure. 



Clean cultivation. 



The puddling of the soil in irrigation. 



The bud moth, which injures the leaf 

 buds. 



Cut worms which work on the leaves 

 and buds. 



Some kind of bacterium or microbe. 



An enzymatic ferment, induced by in- 

 jury to the bark of the roots. 



A rapid evaporation from the leaf. 



Lack of aeration of the soil. 



Hard pan. which retards root develop- 

 ment. 



Scab soil, which lacks plant food. 



Lack of proper drainage. 



Cramping the roots in planting. 



An anemic condition of the tree simi- 

 lar to anemia in the human organism. 



Some of the replies included more than 

 one cause, giving evidence that the wri- 

 ters had observed it under conditions that 

 were dissimilar. 



Method of Investigation 



In my investigation, I applied two 

 modes of reasoning. The first was in- 

 ductive, in which, by the examination 

 and study of a large number of cases, I 



