The Delta independent., 1902-05-09
APPLE TREE ROSETTE.
New and Peculiar Disease OF Apple
Trees on the Rogers Mesa.

From Bulletin No. co. Agricultural College.
A peculiar condition OF apple trees
was brought to our attention on Rogers
mesa in Delta county by tho Horticul-
tural Inspector. More or less OF the
trouble occnrs in a number OF orchards
in this locality. consequently it is a mat
ter OF considerable interest in the coun-7
ty. Some OF the trees are dying. while
there are a number Of dead limbs on
others, but the characteristic feature Of
the disease is = tuft or rosette OF small
leaves at the end OF brauches that are
Otherwise nearly bare OF foliage. The
similarity OF this condition TO the peach
tree rosette. a common disease in pOr-
lions OF the Southeast. was so great that
the presence OF a new apple tres diseass
Was suspected.
i visited this section in July and col,
!ected numerous specimens. bat no par.
asitic organism could be detected BY
la laboratory Investigation. Later on Mr.
9. II. Potter visited some OF these or
chsrds and made valuable observations
on the soil formation. visited the io-
caliiy sgsin in September in company
with DR.. Headden. and as result OF
our observations and study, together
with the experience OF the fruit grow
ers. we arrived at the following conciu-
sions:
Much OF the soil on the mesa contains
an excsss OF mari and in many places
this substance forms asolid substratum.
AT the edge OF one orchard visited thu
owner was digging and burning it to
make cement 10 be used in mason
work. The mari 10 itself ia, perhaps,
not Larmful TO plants: in fact. when ju
diciously applied 10 land it acts AZ q
!iberator OF plan; food. but when pres
ent IN excess tho soil 10 infer,ile. This
is shown by the fact that when roots
penetrate the mari substratum they
send out few OF no iibrous roots. The
roots do not usually penetrate this sub
stratum 10 any extent, consequently tho
tiecs are often shallow rooted in or
chards where The layer OF mari is close to
the surface TIE level OF The lowest
roots on ons dying tree was only ten
inches below the surface OF the soil
Al this depth they btanched out hori-
&on,aiiy. where they were readily in
jured by lack Of moisture and by tho &C.
,ion of frost. But q more immediato
cAuse for this condition OF the treee{s
found 10 the water supply. Water ~
plentiful drrirg tie earlier part et ~
Gem. .. but in the Jauss part u j ,sav,
the supply fas usually been exsGusted.
The nature o! the coil Is such that it
readily dries out and the trees suffer
for moisture. consequently growth stops
and the tissues harden. In the after
part Of July partial supply OF water is
agaiu TUNED into the diiches and the
orchards are irrigated. The result i.
that in many instances these trees make
u distinct second growth which is im
mature when cold weather comes on.
Those branches which are not killed
but arc severely injured dur
ing the winter put forth feeble growth
the follow ing spring. The end bud. Is
uaily being the strongest, lives at Ibe
expense OF the others, consequently
many of the side buds soon die IL they
start into growth at all, and the tcrmin-
al one develops a contracted branch 90
which the leaves are crowded, thus form
ing the rosette.
Second growth 10 not always ucccs
sary. however. for the appearance o.
this disesse. Shallow rooted trees plant
ed in a soil that is quickly dried out are
easily injured during the w;o,er. This
proba bly, Rccounts for the fact that tue
first attracted general attention
after the hard winter OF 1895 %.
One orchard wac visited in which a
small number OF diseased branches had
appeared, but which had been promptly
removed or severely cut back early in
the spring, At this date. October ;, the
trees appeared to be perfectly healthy
and had made a vigorous growth which
showed no sign OF disease This expert
mcut tends TO confirm the conclusion
that the difficulty is due to local oondi-
tione and not to specific organism
which might spread to- other portions OF
the valley.
Apparently the same difficulty is tlg
ured and described in a recent Califor
MA bulletin in which tho author as
cribcs the cause to the presence OF aka
lies in the soil. He states that apple
trees are injured "by l.20a pounds OF
salt per aero distributed through four
feet Depth
The particular soil on Rogers mesa
that was examined contained l.S2O
pounds OF common salt per acre taken
TO depth OF one foot. While this is
much larger amount OF salt than the .
trees are said to be able TO endt!ro in
most OF the trees do not show
any sign OF The affection. though they
have been planted nine years This
statement is consigned to the fret foot
OF soil, because II 10 doubtful il there is
any portion OF the orchard whore the 4,
soil is four feet deep. Moreover, the
subsoil is q mari into which the trees
had thrown verv few roots.
The amount OF sodic carbonate in this /
soil wps not determined. However. We
have had occasion to observe nursery .
that WAS established in soil In which .
tho sodic carbonate content was deter
mined and found to be 2soo pounds per
acre. taken to depth OF four feet. The .
trees made an excellent growth for three .
years and showed 10 sign OF the rosotte .
affection.
While these observations do not prove
that this condition OF apple trees may
not be produced by the action ot aka
'ies. they point to the conclusion that
such an effect 10 improbable under our
Treatment-A nnle trsa. ab nrl5 pnt ba