River Falls journal. [volume] (River Falls, Pierce County, Wis.) 1872-2019, 1914-06-04
TWO SERIOUS BEAN DISEASES
How TO CONTROL THEM


igan alone estimated at 1000, 900
or 20 per cent of the crop of 1913.
This state does not stand alone
for similar conditions obtain in
other bean-growing sections. 1t
is becoming more difficult each
year to secure bean seed free from
one or both of these diseases. In
view of these facts, it is highly
important that the diseases be
more thoroughly recognized and
that the best available methods OF
control, some of which must be
begun in the early cultivation of
the plants, be understood and put
into practice.
Cause Of Bean Anthracnose
Bean anthracnose is caused by
a fungus which attacks the stems,
leaves, pods and seeds Of the
plants. On the stems and leaf
veins it causes elongated, sunken,
dark-red cankers, sometimes kill
ing young plants and often pro-
ducing deformed and yellow
leaves. Rounded or irregular
sunken spots with a slightly rails
ed rim are produced on the pods.
The spots usually have pink cen
ters surrounded by a dark red
dish border. In severe cases the
pods may be entirely covered by
the sores and produce no seed. In
other cases the fungus penetrates
the pods and enters the seed, caus-
ing dark sunken specks or spots.
In these diseased seeds as well as
in the refuse from diseased plants
the fungus is propagated from
season to season.
Cause OF Bean Blight
The bean blight differs from an
thracnose in several ways. 1t is
caused by a bacterial organism. On
the leaves it produces irregular,
diseased areas which at first have
a water-soaked appearance, later
dry out and become brown and
brittle. The entire margin or half
of a leaflet is often affected. On
the pods the disease starts as
slightly raised and watery pus-
tules, which later enlarge, become
Of irregular shape and amber col
or with yellow centers. Infected
seed show yellow diseased blot
ches or are entirely yellowed and
shriveled.
Nature OF Loss
Both diseases cause serious los
ses in the snap bean trade. Dis
eased pods are unmarketable and
must be sorted out. If but a few
slightly spotted pods r packed
in a basket the disease may spread
during shipment. causing addition
al loss and necessitating extra
sorting before the beans a be
sold to the consumer. In the seed
bean trade all beans must be hand
picked to get out the discolored
diseased seeds. From Is to 80 per
cent of diseased beans are fire.
ouentIy sorted out, which involves
a heavy loss of beans as we'll as
the cost of sorting. Diseased
beans used for seed usually give
a poor stand and result in the pro
duction of a badly diseased crop.
Control Measures
Tt has been c~onclusively demon
strated that anthracnose a be
avoided by a careful system OF
seed selection. Save seed from
perfectly healthy pods, selected
with great care for entire absence
of spotting. Carefully keep them
away from diseased pods, shell by
hand to avoid r~einfection, an q
plant on clean land. Pull and burn
any plants showing disease. BY
planting the seed thus secured
enough ~disease-free seed can be
secured to plant the whole crop.
In the absence Of such disease
free seed ~ secure for planting,
seeds having the least possible
amount of disease, as shown by
actual examination; ~ all seed
should be hand-picked and no seed
showing the slightest di~scoloration
should be planted; (3) practice
crop rotation, plant beans
on land Where the same crop grew
the previous season; az do not
cultivate or walk through the bean
field or pick beans while wet with
dew or rain. If the disease is pre-
sent it is then easily spread from
one part Of the field to another.
The bean blight is more difficult
to control than a~nthracnose, but
the same methods will give the
best results at present available.