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ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 



aphids subsist on the plant juices, feeding 

 by means of feeding or sucking beaks. 

 Wherever they feed, galls of greater or 

 lesser size are produced." 



In this bulletin then we have it taught 

 that aphis produces gall and that gall 

 produces on the top a condition similar 

 to what we call rosette. 



Professor Ralph E. Smith, of the Cali- 

 fornia University, says: "Rosette may be 

 classed with 'Die Back,' 'Little Leaf," and 

 'Club Tip.' " "The symptoms are a stunted, 

 weak growth of the shoots." "Such ef- 

 fects are produced most commonly per- 

 haps, by a long continued dry season in 

 the fall, causing the trees to become speci- 

 ally dormant, followed by warm spring- 

 like weather during the winter, soon after 

 the first rains." "But apple rosette may 

 be caused by unfavorable soil conditions, 

 or unfavorable climatic conditions which 

 check the growth of the terminal buds." 



California Bulletin No. 218 says: The 

 disease called in California "Club Tip" 

 seems to us the same as that which in 

 Washington and Oregon is generally 

 known as "Apple Rosette." 



Professor Wickson, of the University of 

 California, says: "Lack of proper mois- 

 ture may cause the root hairs to perish, 

 as well as too much moisture, alkali or 

 other causes. These conditions are mani- 

 fest in 'Die Back," 'Yellow Leaf,' and 

 other forms of ailment on the tips of 

 the branches." 



Professor A. D. Selby, of the Ohio Agri- 

 cultural College, says: "Peach Yellows 

 and Peach Rosette are similar diseases. 

 If not identical in origin. They are 

 caused by an enzymatic ferment which 

 causes a physical breakdown of sap 

 cells and chlorosis, or yellowing of the 

 leaves." See Ohio Bulletin 214. 



Henry Marshall Ward, Professor of 

 Botany, Cambridge, England, says: "All 

 important results of bacteria are due to 

 poisonous bodies or toxins formed by 

 them. Bacterial infection is in the na- 

 ture of an intoxication. They, however, 

 multiply living organisms in the tissues 

 which fact regulates the supply of toxins. 



"The effects produced are as follows: 



"1. Tissue changes in the vicinity of the 

 bacteria. 



"2. Tissue changes produced at a dis- 

 tance by the absorption of their toxins. 



"3. Degeneration and death of the cells." 



M. L. Dean, State Horticulturist, 

 of Montana, says: "Rosette is an 

 anemic condition of the tree similar in 

 nature to anemia in the human organism. 

 When there is a lack of vital force on 

 account of lack of food, or lack of assimi- 

 lation of food, this disease may appear." 



Professor W. S. Thornber, formerly of 

 Washington State College, said: "We 

 have learned that by cutting off the sur- 

 face roots of young growing trees, as is 

 done by the cultivator on soil underlaid 

 with hard pan, we produce a yellow, 

 starved growth, known as winter desicca- 

 tion or fruit tree rosette." 



T. O. Morrison, Washington State 

 Horticulturist said: "I do not be- 

 lieve rosette is a disease, because I 

 have been unable to grow a culture of it 

 in potato agar. It is a condition, not a 

 disease. I believe that a very unbal- 

 anced condition between the roots and 

 the top will produce it. In many cases, 

 I believe, it has been caused from girdling 

 the roots by gophers, or root pruning to 

 produce fruitfulness, clean cultivation, or 

 lack of available nitrogen." 



Clarence Starcher, former fruit inspec- 

 tor, said: "In my opinion, the cause is 

 lack of nutrition, or an unbalanced soil 

 condition. This may result from lack of 

 proper drainage, too heavy manuring of 

 shallow soils, or a combination of too 

 heavy manuring and lack of drainage." 



Dr. P. W. Cornue, fruit grower, said: 

 "I would call it a disease of malnutrition. 

 It may be lack of an available balance 

 ration as in drought, where the food is 

 not in solution; or mechanical injuries to 

 roots or limbs, including winter injury; 

 or constriction as from galls; or an un- 

 balanced ration as an excess of some ele- 

 ments and a deficiency of others, as too 

 much alkali, too much horse or hen 

 manure." 



Dr. P. F. Gray said: "Apple rosette Is 

 caused by lack of air, which causes nod- 

 ules to form on the roots and prevents 



