Foot & Crown Rots- Monocots

Question 1

List four disease names that affect monocots….

Answer 1

Take All
Common Root Rot
Fusarium Crown Rot
Eyespot (Strawbreaker)

Question 2

Residue-Borne Pathogens

Answer 2

Residue acts as a protection from the environment. Sustenance during intercropping periods. Management of crop residues is important.

Question 3

Take All

Answer 3

Take all is a BIOTROPH that feeds on live tissue, it is a sophisticated pathogen.

Question 4

Take-All teleomorph name.

Answer 4

Gaeumannomyces graminis

Question 5

Gaemannomyces graminis

Answer 5

Leads to a Haustoria, a feeding structure going in to the plant from the root. It forms an intimate relationship with root cells. It also can affect turfgrass.

Question 6

Causes of Take All….

Answer 6

Irrigate or high rainfall
Wheat on wheat
Residue borne disease (dead tissue of previous crop) NO TILL

Question 7

Take-All Controls

Answer 7

1. Crop rotations with 2 years out of cereal crops (rotate to dicot)
2. Take all decline after continuous small grain production, actively letting biocontrol take over.
3. For lawns pH>6 encourages decline
4. Manganese fertilizers

Question 8

Common root rot primary infection court….

Answer 8

Sub-crown internode.

Question 9

Symptoms of common root rot….

Answer 9

Brown roots on subcrown internode.

Question 10

Common Root Rot teleomorph name.

Answer 10

Cochliobolus sativus.

Question 11

Cochliobolus sativus….

Answer 11

Common Root Rot
Enters through the subcrown internote (chocolate brown)
Restricted primarily to the crown and sub crown internode.

Question 12

Common Root Rot Controls….

Answer 12

1. Plant shallow: Risk of infection has been correlated with the length of the subcrown internode.
2. Rotate: Rotation between wheat and barley.
3. No-till: Residues appear to reduce disease
4. Potassium? reduces spot blotch

Question 13

Fusarium Crown Rot (teleomorph names)

Answer 13

F. Culmorum
F. Pseudograminearum
F. graminearum (corn)

Question 14

Symptoms of Fusarium Crown Rot

Answer 14

1. Rot extends above the crown.

2. White heads in drought stricken fields, tillers abort with white heads.

Question 15

Causes of Fusarium Crown Rot…

Answer 15

1. Infection requires spring moisture
2. Disease most severe when plants become water stressed.
3. Susceptible plants are Durum, Spring, Winter wheat due to Water Use Efficiency.
4. ^ FCR Under No-Till

Question 16

Why is planting depth important for FCR?

Answer 16

Deep crowns enable the pathogen to attack stem directly.

Question 17

FCR controls…

Answer 17

1. Crown depth
2. Planting depth
3. Furrow closure
4. Genetics
5. Soil temperature

Question 18

More controls for FCR?

Answer 18

1. Reduce seeding density?
2. Reduce nitrogen application?
3. Seed treatments
4. Plant early or late (WW)
5. Ensure proper crown depth, make sure furrow closes
6. Maximize distance from previous residue (3 inches) (perpendicular to planting)

Question 19

Eyespot teleomorph name.

Answer 19

Pseudocercosporella herpotrichioides.

Question 20

Causes of eyespot…

Answer 20

• 50 degrees F or less, and stops above 60.
• Cold weather pathogen
• Humid/wet (low lying areas)
• Cereal Crop: winter wheat

Question 21

Eyespot controls….

Answer 21

1. Rotations: Two years of spring crops (not cereals)
2. Plant late/reduce stand: Reduces humidity
3. Plant cultivars which resist lodging (stronger stems)