The Kennewick courier. [volume] (Kennewick, Wash.) 1905-1914, 1911-07-21
CONCERNING THE APPLE ROSETTE

mas had many inquiries regarding
apple rosette, he recently wrote to
the department of agriculture, and
has received the following reply from
M. B. Waite, Pathologist in charge
OF Fruit Disease Investigations, De-
partment Of Agriculture.
F. E. DeSellem, Prosser, Wash.
We note your experience in
treating tree with stable manure
and add that this is quite a common
experience with apple rosette. 1t
will hardly be necessary for me to
examine the roots as this is typical
material. The point, of course,
about rosette trees is that the roots
are practically normal or uninjured.
| am sending you what little infor-
nation we have about the disease.
The apple rosette is entirely soil
or nutrition trouble and is therefore
OF a physiologal nature. It is an
entirely different type of disease
from the peach rosette. The peach
rosette is a contagious disease re-
lated to peach yellows, while the
disease known as apple rosette is
not contagious, and is not caused
by any parasite. The cause of the
rosette of the apple is not known.
1t is generally associated with ex-
cessive amounts of lime either in
the form of ordinary lime or gypsum.
The presence Of gypsum beds or
lime beds underneath or at too close
a distance is often sufficient cause
OF the trouble. Frequently, how
ever, exactly the same disease
occurs on alluvial or colluvial soils
which are not underlaid by lime or
gypsum beds. In these cases, how
ever, the same material exists in
the soils washed down from the
hills. Rosette is practically limited
to the arid regions. It probably is
related in some way more or less
closely to the trouble called chloro-
sis. Both these diseases are rare
where there is an excess of rainfall
to wash the lime and other soluable
materials out of the soil, but are
common in districts with restricted
rainfall. There has been theory
advanced that chlorosis is due to
the formation of nitrites instead of
nitrates in the soil. The nitrites are
poisonous while the nitrates are not
except in excessive quantities. This
same theory would probably apply
to apple rosette as we'll as chlorosis.
Stable manure has been used and
has a beneficial effect on trees effect
ed with rosette, though its action is
not quite understood. You might
try it on part of your trees, but 1
am not at all certain that it will be
of much benefit -
Add ed to this Mr.. DeSellem has
the following to say:
Il have five orchardists in three
countries who are experimenting on
the apple rosette," and would
like to hear from others who are
trying different methods to effect a
cure. I find this disease every
where l go, and one orchardist claims
that it is caused by not painting
the wounds when the trees are
pruned, thereby causing the heart
of the tree to begin to decay. He
also says that the 'rosette' shows up
more on the grated trees. From
observation believe that Mr.. M. B.
Waite is right in his theories, l
have never seen the rosette in an
orchard that has been planted to
some cover crop two or three years
and plowed under. At Hooper,
Wash. there are-1S acres of 12-year-
old trees, about ten acres has had
alfalfa growing in it for several
years, and it has no apple rosette
but the other part which has never
had a cover crop on it shows the
apple rosette,' so that I am con-
WINGED that it is lack of plant food
in the soil.
IF. E. DeSellem."