484 
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 BE. 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: “ATI 
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: 
ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 
“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 treées, 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: 
“T 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. F. F. Gray said: ‘Apple rosette is 
caused by lack of air, which causes nod- 
ules to form on the roots and prevents 
