Agriculture Reference
In-Depth Information
Disease
Principal
pathogen(s)
Primary
infection
site
Primary symptoms Conditions leading
to highest disease
s
everity
Practices that generally
minimize crop damage
Efficacy of
seed-applied
fungicides
Efficacy of
genetic
resistance
Common root
rot
Bipolaris
sorokiniana
stem base,
crown,
subcrown
internode
lesion on
subcrown
internode;
stunting;
w
hiteheads
cultivation;
planting wheat
annually; drought
crop rotation; summer
fallow; shallow sowing;
delay autumn planting
date; plant resistant
c
ultivar
poor to fair
poor to
fair
Fusarium crown
rot
Fusarium culmorum
,
F. pseudograminearum
stem base,
crown,
subcrown
internode
browning of lower
leaf sheath;
lesion on
subcrown
internode; dry
rot of crown and
r
oots; whiteheads
no-till or minimum
tillage; host crops
annually or 2-year
rotations; planting
winter wheat too
early; high N
f
ertility; drought
destroy infested crop
residue; crop rotation;
judicious application of
N; delay autumn planting
date; plant resistant
cultivar; shallow sowing
poor; more
effective for
spring than
autumn
plantings
poor to
fair;
currently
not widely
deployed
Pythium root
rot
Pythium ultimum,
P. irregulare,
and others
seed, roots seed rot;
damping-off; root
rot; stunting;
delayed maturity
cool, wet soil;
planting host crops
annually; planting
winter wheat too
late or spring wheat
t
oo early
plant when soil
temperature favors rapid
seed germination; band a
starter fertilizer below
seed; control green
b
ridge; plant fresh seed
poor to fair;
more effective
for spring
than autumn
plantings
not
available
Rhizoctonia
root rot
Rhizoctonia solani
AG-8,
R. oryzae
roots
root rot;
stunting; delayed
maturity
no-till; planting
host crops annually;
planting winter
wheat too late or
spring wheat too
e
arly
control green-bridge;
disruption of seed row
at planting; pre-plant
tillage; band a starter
fertilizer below seed;
s
ummer fallow
poor for wheat
planted in
autumn; poor
to fair for
spring wheat
not
available
Take-all
Gaeumannomyces
graminis
var.
tritici
,
G. graminis
var.
avenae
roots
root rot;
stunting;
blackened stem
base in wet or
humid sites;
whiteheads
planting host crops
annually; planting
winter wheat too
early; major
increase in soil pH
after lime
a
pplication
crop rotation; control
green-bridge; manage
form of N absorbed by
roots; delay autumn
planting date
poor to fair;
more effective
for spring
than autumn
plantings
not
available
Cephalosporium
stripe
Cephalosporium
gramineum
roots &
crown
long leaf stripes
merging into dark
veins in leaf
sheath; stunting;
whiteheads
no-till or minimum
tillage; acid soil;
host crops annually
or 2-year rotations;
planting winter
wheat too early;
freeze/thaw cycles
d
uring winter
crop rotation; plant
resistant winter wheat;
plant spring wheat;
destroy infested crop
residue; lime acid
soils; control green-
bridge; delay autumn
p
lanting
not effective fair to
good
Eyespot
Oculimacula
yallundae
,
O. acuformis
stem base elliptical
lesions on lower
culm; plant
lodging;
whiteheads
host crops annually;
planting winter
wheat too early
plant resistant winter
wheat; delay autumn
planting date; plant
spring wheat; crop
rotation; apply foliar
fungicide
fair to good;
not necessary
for spring
plantings
good
