Laurel outlook., 1950-08-09
Observation-Disclosures h,H'.ttnf'isiib
Yard and Garden
By Leonard wager
Assistant Horticulturist
Montana Extension Service
Disease In the Garden

t a to u own. Some become sic.
, because of some physical disturb
ance such as lack of some neces
sary plant food elements, no
enough or too much water. Other
succumb to the entry of a foreigl
l BODY such as a fungus, bacteria O
virus to produce disease.
Some plant ills we can remedy
Tor others we a do nothing. Tn,
causes of some plant diseases ar,
readily recognized, while others ar,
difficult to spot. A whole group Of
the same species of plant may be.
come affected with the same dis.
ease, or another disease may occur
only in isolated specimens.
1t is the job of the plant doctor
more properly known as the plant
p~athologist, to diagnose any plant
disease, he can do a much better
job if he has a thorough case his
tory OF the plant.
Diseases due to some physical
upset of the plant are referred
to as physiological diseases. Lack
OF certain elements in a soil will
manifest certain foliage symptoms
on various species of plants. A
common condition found in certain
areas Of the state is known as
llme-induced chlorosis. The leaves
OF certain plants become yellow
particularly between the veins of
the leaves.
A high lines condition in certain
soils makes the iron in the soil I'M
available to plants. Iron is neces-
sary for the green coloration of
the leaf and hence the reason for
the following or acknowledgements
ance of the foliage of the plant.
Treatment of the soil to reduce it's
a~lkalinlty is the remedy frequently
suggested for this condition.
Another good example of a ply
siologic disease is the commonly
occurring blossom end rot of to-
mato fruits. An uneven moisture
supply during the season will cause
this. There is little evidence OF
this disease if the plants receive
an ample supply of moisture all
through the growing season.
Certain fungus diseases attack
plants in various ways. Some live
IN the soil like the diseases which
cause scab and fusarium wilt in
potatoes. Others are carried as
spores from some initial source of
Infection to attack new plants.
Mlldews and the foliage blights of
potatoes are examples of these.
Many of these diseases can be con-
trolled by spraying plants with
copper-containing fungicide like
Bordeaux, or ones of the newer
organic fungicides. Fine sulphur is
used also for the control of various
foliage diseases like mildews.
Many foliage diseases spread
more rapidly when plant leaves are
vet. Hence it is often desirable to
water plants during the early part
If the day so they have a chance to
Try off before nightfall.
Not all diseases can be controlled
~ spraying. Some diseases are
.ystemic in nature. That is, they
invade the plant sap, and nothing
'osslble can be done, save kill the
liant, to conrtOl them. Most of our
liant viruses and some bacterial
lseaseS are of this nature.
Bacterial blight and halo blight
i beans are two very common
acterial diseases that are systemic
I nature. They pass from genera
to generation in (and not on)
ne seed of the plant. Splashing
aims, human being, animals and
lsects are all responsible for
preading the disease from one
liant to another. The two diseases .
Dread like wildfire especially dur
lg cool, wet weather. For that ,
eason, N is cautioned never to
ork in, or pick beans when the ,
Iants are wet with dew or rain.
he only way to be free of these ,
.seases is to use disease free seed ,
rown in certain areas of the west
aving your own seed is one sure =,
ay of inviting trouble from those :
seaseS. T
Fire-blight is another disease of I
is nature. 1t attacks apples and S
,ars especially at the tips Of 2
.anches and blossom clusters A
using a scorched appearance of a
csc parts. The bacteria enters fl
csc plants chiefly at blossom
ne and is transmitted by the t,
es during the act of pollination. Il
To avoid fire-blight, n should s.
frain from planting highly sus- A
ptible varieties especially in Il
cas- where this disease is preva- d
1t. Cutting out infected branches "
ii below the area of infection is
ggested if the disease is already d
esent. One should take care by p
injecting the pruning equipment =,
.er each cut in mercuric chloride u
ution C:1000), to prevent "