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GREEN BEANS AND PEAS

Aphanomyces root rot
Page 134

Ashy stem blight (charcoal rot)
Page 138

Black root rot Page 142

Black spot Page 146

Fusarium root rot
Page 150

Pea wilt Page 154

Pythium stem rot
Page 158

Rhizoctonia root rot
Page 162

Sclerotinia rot (white mould)
Page 166

Sclerotium rot Page 170

132 SOIL-BORNE DISEASES IN VEGETABLE CROPS

SOIL-BORNE DISEASES IN VEGETABLE CROPS 133

GREEN BEANS AND PEAS
APHANOMYCES ROOT ROT
Aphanomyces euteiches
WHAT SHOULD I LOOK FOR?

GREEN BEANS AND PEAS | APHANOMYCES ROOT ROT

Initial honey-brown discolouration of root and area above the seed up to the soil line as shown in plants on right hand side, compared to healthy plants on the left. Nodulation on roots may also be poor. Roots become darker as disease progresses and eventually die
L. Porter, ARS USDA

WHERE WILL I SEE SYMPTOMS?

FAVOURABLE CONDITIONS FOR DISEASE DEVELOPMENT

ROOTS

STEM

134 SOIL-BORNE DISEASES IN VEGETABLE CROPS

WARM

WET

• 22-28ºC

Aboveground yellowing will occur starting at the bottom leaves, followed by wilting and death

DISTRIBUTION IN THE FIELD
SCATTERED Individual/small patches of
infected plants

HOW DOES IT SPREAD?

WIND

FREE WATER

MOVEMENT OF CONTAMINATED
SOIL

CONTAMINATED PLANT DEBRIS

SURVIVAL TIME WITHOUT HOST

Mo
SOIL-BORNE DISEASES IN VEGETABLE CROPS 135

FALLOW/COVER CROP

HOW DO I CONTROL IT?
FARM HYGIENE
Stop movement of contaminated soil, water, plants and equipment
STOP

CROP ROTATION
Select non-host rotation or cover
crops

HOST-FREE ZONE
Control volunteer host plants and weeds

• 6 to 10 year rotation

SOIL TEST
Conduct a pre-sowing soil test to help predict
level of risk

NO RESIDUE AT
PLANTING
Ensure no plant residues from host crops at planting

DRAINAGE
Plant on raised beds or
well-draining soil

PLANTING PREPARATION

POST-PLANT

IRRIGATION
MANAGEMENT
Monitor crop and soil to optimize
amount and timing

CONTROL PESTS
Control insect pests that
spread spores
• Sciarid flies can spread spores and larvae damage roots

HOST RANGE
Range of legume crops and weed species including peas, beans, clovers and medics
136 SOIL-BORNE DISEASES IN VEGETABLE CROPS

BIO FUMIGATION
Grow a biofumigant crop

CHEMICAL FUMIGATION
Always use with care and as per
label

IMPROVE SOIL HEALTH
Add organic matter or amendments to
boost beneficial microbes

• Consult APVMA or InfoPest website for current registered products

CROP SELECTION
Choose a resistant/less susceptible cultivar

• Avoid late-maturing varieties especially in paddocks with history of Aphanomyces root rot

SOIL-BORNE DISEASES IN VEGETABLE CROPS 137

GREEN BEANS AND PEAS | APHANOMYCES ROOT ROT

GREEN BEANS AND PEAS
ASHY STEM BLIGHT (CHARCOAL ROT)
Macrophomina phaseolina
WHAT SHOULD I LOOK FOR?

GREEN BEANS AND PEAS | ASHY STEM BLIGHT (CHARCOAL ROT)

Sunken lesions develop on the stem, as shown here in seedlings. Lesions have sharp

margins and may contain concentric rings

H. Schwartz, Colorado State University, Bugwood.org

WHERE WILL I SEE SYMPTOMS?

FAVOURABLE CONDITIONS FOR DISEASE DEVELOPMENT

STEM

WARM

DRY

• 24-27ºC

138 SOIL-BORNE DISEASES IN VEGETABLE CROPS

As the disease progresses, dry rot of the stem and pale, ash-coloured “dust” develop
H. Schwartz, Colorado State University, Bugwood.org

Small black survival structures (microsclerotia) develop in dead tissue
P. Bachi, University of Kentucky Research and Education Center, Bugwood.org

DISTRIBUTION IN THE FIELD
SCATTERED Individual/small patches of
infected plants

HOW DOES IT SPREAD?

FREE WATER

MOVEMENT OF CONTAMINATED
SOIL

SURVIVAL TIME WITHOUT HOST

Mo
SOIL-BORNE DISEASES IN VEGETABLE CROPS 139

FALLOW/COVER CROP

HOW DO I CONTROL IT?
FARM HYGIENE
Stop movement of contaminated soil, water, plants and equipment
STOP
CROP SELECTION
Choose a resistant/less susceptible cultivar

CROP ROTATION
Select non-host rotation or cover
crops
• 4 to 6 year break from susceptible crop
USE CLEAN SEED OR
SEEDLINGS
Source seed/ seedlings from a certified reputable
source

IMPROVE SOIL HEALTH
Add organic matter or amendments to
boost beneficial microbes
NO RESIDUE AT
PLANTING
Ensure no plant residues from host crops at planting

PLANTING PREPARATION

POST-PLANT

AVOID WATER STRESS
Ensure plants receive adequate
water

GOOD NUTRITION
Ensure plants’ nutritional needs
are met

AVOID PLANT INJURY
Avoid any physical damage to plant

• Avoid excess Nitrogen
HOST RANGE
Very wide, host range infecting over 500 plant species including members of the pumpkin, bean, brassica and pepper families. 140 SOIL-BORNE DISEASES IN VEGETABLE CROPS

SOIL SOLARISATION
Cover soil with a tarp and kill
harmful pathogens

BIO FUMIGATION
Grow a biofumigant crop

SOIL TEST
Conduct a pre-sowing soil test to help predict
level of risk

CHEMICAL TREATMENT
Treat seed/ seedlings with registered fungicide
• Consult APVMA or InfoPest website for current registered products

SOIL-BORNE DISEASES IN VEGETABLE CROPS 141

GREEN BEANS AND PEAS | ASHY STEM BLIGHT (CHARCOAL ROT)

GREEN BEANS AND PEAS
BLACK ROOT ROT
Thielaviopsis basicola (aka. Chalara elegans)
WHAT SHOULD I LOOK FOR?

GREEN BEANS AND PEAS | BLACK ROOT ROT

Initially long red lesions appear on the root which eventually turn black
Virginia Tech Learning Resources Center

WHERE WILL I SEE SYMPTOMS?

FAVOURABLE CONDITIONS FOR DISEASE DEVELOPMENT

ROOTS
142 SOIL-BORNE DISEASES IN VEGETABLE CROPS

WARM

WET

• 17-25ºC

Tap root may become stunted, aboveground plant may also become stunted, wilt and

possibly die

N. Cattlin, Alamy Stock Photo

DISTRIBUTION IN THE FIELD
SCATTERED Individual/small patches of
infected plants

HOW DOES IT SPREAD?

MOVEMENT OF CONTAMINATED
SOIL

CONTAMINATED PLANT DEBRIS

SURVIVAL TIME WITHOUT HOST

Mo
SOIL-BORNE DISEASES IN VEGETABLE CROPS 143

FALLOW/COVER CROP

HOW DO I CONTROL IT?
FARM HYGIENE
Stop movement of contaminated soil, water, plants and equipment
STOP
NO RESIDUE AT
PLANTING
Ensure no plant residues from host crops at planting

CROP ROTATION
Select non-host rotation or cover
crops

IMPROVE SOIL HEALTH
Add organic matter or amendments to
boost beneficial microbes

• 5 to 6 year break from host crops
DRAINAGE
Plant on raised beds or
well-draining soil

BIO FUMIGATION
Grow a biofumigant crop

PLANTING PREPARATION

POST-PLANT

IRRIGATION
MANAGEMENT
Monitor crop and soil to optimize
amount and timing

AVOID PLANT INJURY
Avoid any physical damage to plant

• Minimise irrigation splash
HOST RANGE
Wide host range, including beans, peas, cotton, lettuces, lucerne, lupin and soybean
144 SOIL-BORNE DISEASES IN VEGETABLE CROPS

SOIL-BORNE DISEASES IN VEGETABLE CROPS 145

GREEN BEANS AND PEAS | BLACK ROOT ROT

GREEN BEANS AND PEAS
BLACK SPOT (ASCOCHYTA BLIGHT)
Didymella pinodes often in a disease complex with Phoma medicaginis var. pinodella,
WHAT SHOULD I LOOK FOR?

Phoma Koolunga and Didymella pisi.

GREEN BEANS AND PEAS | FAMILYBLACK SPOT (ASCOCHYTA BLIGHT)

Irregular dark brown to black spots that develop into large purplish-black lesions on stems,

leaves and pods. 

M. Wunsch, North Dakota State University

WHERE WILL I SEE SYMPTOMS?

FAVOURABLE CONDITIONS FOR DISEASE DEVELOPMENT

WHOLE PLANT

ROOTS

• In severe cases

146 SOIL-BORNE DISEASES IN VEGETABLE CROPS

WARM
• 18-22ºC

WET

Concentric rings and black survival structures (pycnidia) can often be seen in the middle of

the lesion. 

M. Wunsch, North Dakota State University

DISTRIBUTION IN THE FIELD
SCATTERED Individual/small patches of
infected plants

HOW DOES IT SPREAD?

INFECTED SEED/ SEEDLINGS

MOVEMENT OF CONTAMINATED
SOIL

CONTAMINATED PLANT DEBRIS

SURVIVAL TIME WITHOUT HOST

< 33-y1e0arysears

SOIL-BORNE DISEASES IN VEGETABLE CROPS 147

GREEN BEANS AND PEAS | FAMILYBLACK SPOT (ASCOCHYTA BLIGHT)

HOW DO I CONTROL IT?

FALLOW/COVER CROP

FARM HYGIENE
Stop movement of contaminated soil, water, plants and equipment
STOP

HOST-FREE ZONE
Control volunteer host plants and weeds

CROP ROTATION
Select non-host rotation or cover
crops

• Minimum 3 year break and 500m from previous host crops

PLANTING PREPARATION

NO RESIDUE AT
PLANTING
Ensure no plant residues from host crops at planting

USE CLEAN SEED OR
SEEDLINGS
Source seed/ seedlings from a certified reputable
source

ADJUST DATE
Adjust planting/harvest date to reduce
infection risk

• Avoid early planting at high seeding rates which increases exposure
HOST RANGE Most severe on peas, but also infects lentils, alfalfa, faba beans, clover and vetch
148 SOIL-BORNE DISEASES IN VEGETABLE CROPS

AIR CIRCULATION
Increase row/plant spacing to improve
air flow

CHEMICAL TREATMENT
Treat seed/ seedlings with registered fungicide

• Consult APVMA or InfoPest website for current registered products

SOIL-BORNE DISEASES IN VEGETABLE CROPS 149

GREEN BEANS AND PEAS
FUSARIUM ROOT ROT
Fusarium solani f. sp. phaseoli
WHAT SHOULD I LOOK FOR?

GREEN BEANS AND PEAS | FUSARIUM ROOT ROT

Aboveground plants may initially appear yellow, stunted and wilted and eventually may die
H. Schwartz, Colorado State University, Bugwood.org

WHERE WILL I SEE SYMPTOMS?

FAVOURABLE CONDITIONS FOR DISEASE DEVELOPMENT

ROOTS
150 SOIL-BORNE DISEASES IN VEGETABLE CROPS

COOL
• Soil <13oC at planting

COMPACTED SOIL

Belowground lower root may die off and secondary roots may form above the diseased area
H. Schwartz, Colorado State University, Bugwood.org

Cutting the stem reveals drying out and reddening of the taproot 
H. Schwartz, Colorado State University, Bugwood.org

DISTRIBUTION IN THE FIELD
SCATTERED Individual/small patches of
infected plants

HOW DOES IT SPREAD?

CONTAMINATED PLANT DEBRIS

INFECTED SEED/ SEEDLINGS

MOVEMENT OF CONTAMINATED
SOIL

INSECTS

SURVIVAL TIME WITHOUT HOST

Mo
SOIL-BORNE DISEASES IN VEGETABLE CROPS 151
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