Managing Soilborne Managing Soilborne

Plant Diseases and Plant Diseases and

Arthropod Pests of Arthropod Pests of

VegetablesVegetables

Meg McGrath and

Mary Barbercheck

Crop Rotations

Reduce Pest Habitat

Provide Beneficial Habitat

Know Your Pest

Minimal Pesticide Use

Above-Ground Diversity toFavor Beneficials

Pest and Disease Suppression

Minimal Use of SyntheticPesticides & Fertilizers

Minimize Tillage to Conserve OM

Crop Rotations

Add Organic Matter

Below-Ground Diversity

Healthy Soil

In 1 teaspoon of soil there are…In 1 teaspoon of soil there are…

Bacteria 100 million to 1 billion

Fungi 6-9 ft fungal strands put end to end

Protozoa Several thousand flagellates & amoebaOne to several hundred ciliates

Nematodes 10 to 20 bacterial feeders and a few fungal feeders

Arthropods Up to 100

Earthworms 5 or more

Ecosystem Services Ecosystem Services Provided by Soil OrganismsProvided by Soil Organisms

• Decomposition and nutrient cycling

• Carbon sequestration• Maintenance of plant

diversity• Bioremediation• Biological control of

pests

Survival of Soilborne Pathogens and Insect Pests

• In crop debrisIn crop debris• In seedIn seed• On alternate hosts (including weeds)On alternate hosts (including weeds)• As specialized, protective, dormant or As specialized, protective, dormant or

quiescent stage quiescent stage – (e.g., fungal sclerotia, nematode cysts, (e.g., fungal sclerotia, nematode cysts,

pupae)pupae)• In insect or nematode vectors - pathogensIn insect or nematode vectors - pathogens• As saprophytes or by omnivoryAs saprophytes or by omnivory

White Mold

Biocontrol of Soilborne PestsMechanisms

• Direct action on pathogens + invertebrate pests:Direct action on pathogens + invertebrate pests:– Competition (plant pathogens)Competition (plant pathogens)– Antagonism (e.g., antibiotic production)Antagonism (e.g., antibiotic production)– PredationPredation– Parasitism and diseaseParasitism and disease

• Indirect (e.g., through host effect)Indirect (e.g., through host effect)– Induced resistanceInduced resistance– Growth promotionGrowth promotion

Biocontrol of Pests in SoilApproaches

• Conservation Conservation

• Augmentative Augmentative

• Inundative Inundative

• Classical Classical

Biocontrol of Pests in SoilConservation

• Improve environment for beneficial Improve environment for beneficial organisms in fieldorganisms in field– e.g., increase soil organic matter, minimize e.g., increase soil organic matter, minimize

tillage, conserve surface residues tillage, conserve surface residues – Can favor some pathogens and pests!Can favor some pathogens and pests!

Conservation BiocontrolMicroorganisms in SoilBacteria Actinomycetes

Fungi Mycorrhizae

Conservation BiocontrolPredatory Microarthropods in Soil

Mesostigmatid mite

Japygid

Ground beetle andRove beetle larvae

Centipede

Pseudoscorpion

Conservation BiocontrolSoil Surface Beneficials

Ground and Rove Beetles

Conservation BiocontrolSoil Surface

Spiders

Soil Management and European Corn Borer (Phelan et al., 1995)

0

50

100

150

200

250

EC

B E

ggs/

Pla

nt

Unamended NH4NO3 Manure

Organic Conventional

*

Biocontrol of Pests in SoilAugmentation

• Apply products or materials (e.g., Apply products or materials (e.g., compost) to augment beneficial compost) to augment beneficial organisms already presentorganisms already present

• This approach builds populations of This approach builds populations of organisms already present but in numbers organisms already present but in numbers too low for effective pest management too low for effective pest management

Understory Management in Apples(Mathews et al. 2002)

0

50

100

150

200

250

300

350

400

450

Pre

dat

ors

Compost Control Herbicide Plastic

a

b

bb

Understory Management in Apples(Mathews et al. 2002)

1.1

1.15

1.2

1.25

1.3

1.35

1.4

Dia

met

er (

cm)

Compost Control Herbicide Plastic

a

b

b

b

Biocontrol of Pests in SoilInundation

• Apply products or materials in same Apply products or materials in same manner as a pesticidemanner as a pesticide

• This approach introduces large numbers This approach introduces large numbers of organisms for relatively fast-acting of organisms for relatively fast-acting controlcontrol

Products for Soil Arthropod Biological Control

• SteinernemaSteinernema spp. spp.• HeterorhabditisHeterorhabditis

spp.spp.• HypoaspisHypoaspis milesmiles

(predatory soil (predatory soil mites)mites)

• Atheta coriariaAtheta coriaria (generalist (generalist predator)predator)

Signs and symptomsof nematode infection

Biocontrol of Pests in SoilClassical

• Introduce a non-native organisms to Introduce a non-native organisms to control a non-native pest control a non-native pest

• Intention is establishment of beneficial Intention is establishment of beneficial organism for long-term, low input pest organism for long-term, low input pest managementmanagement

Introduce Introduce beneficialbeneficial

Establishment Establishment and controland control

Biocontrol of Pests in SoilSome Challenges

• Soil abiotic or biotic environment may not support Soil abiotic or biotic environment may not support sufficient numbers of beneficials for control sufficient numbers of beneficials for control

• Pest not present or in adequate number to support Pest not present or in adequate number to support beneficialsbeneficials

• Some biocontrols are very specific. Others are Some biocontrols are very specific. Others are generalistsgeneralists

• Environmental conditions affect efficacy; Environmental conditions affect efficacy; performance can be inconsistentperformance can be inconsistent

Biocontrol of Pests in SoilRegulations

• Microbial and chemical products claiming Microbial and chemical products claiming control must be registered as pesticides control must be registered as pesticides with US EPA. Must be registered in state.with US EPA. Must be registered in state.

• Beneficial macro-organisms exempt from Beneficial macro-organisms exempt from EPA registrationEPA registration

• Efficacy data not required for registrationEfficacy data not required for registration• Safety to environment + nontarget Safety to environment + nontarget

organisms is focus of registrationorganisms is focus of registration

Biocontrol of Pests in SoilRegulations

• Efficacy data from replicated experiments Efficacy data from replicated experiments often lacking , especially for vegetable often lacking , especially for vegetable uses!!uses!!

• EPA/IR-4 Biopesticide Demonstration EPA/IR-4 Biopesticide Demonstration Grant ProgramGrant Program

Bacterial and fungal biocontrol species in commercially-available

disease-control products

• Gliocladium virens• Trichoderma harzianum and other species• Bacillus subtilis, B. pumilus, etc.• Pseudomonas syringie• Coniothyrium minitans• Streptomyces sp.

Efficacy - Biocontrol Products - Greenhouse Ornamentals

# Experiments# Experiments

EffectiveEffective IneffectiveIneffective

CompanionCompanion 00 33

DenyDeny 00 11

MycostopMycostop 00 44

PlantShieldPlantShield 00 44

PrimastopPrimastop 11 33

RootshieldRootshield 33 1111

SoilGardSoilGard 22 66

Pathogens: Pathogens: Pythium, Rhizoctonia, Fusarium, ThielaviopsisPythium, Rhizoctonia, Fusarium, Thielaviopsis

Mycostop Biofungicide LabelContents

Keep Out of Reach of Children

CAUTIONPRECAUTIONARY STATEMENTS

Hazards to Humans and Domestic Animals

Harmful if inhaled. Avoid breathing dust or spray mist. Causes moderate eye irritation. Avoid contact with skin, eyes or clothing.

AGRICULTURAL USE REQUIREMENTSUse this product only in accordance with its labeling and with the Worker Protection Standard, 40 CFR Part 170. This Standard contains requirements for the protection of agricultural workers on farms, forests, nurseries and greenhouses, and handlers of agricultural pesticides. It contains requirements for training, decontamination, notification and emergency assistance. It also contains specific instructions and exceptions pertaining to the statements on this label about personal protective equipment (PPE) and restricted-entry interval. The requirements in this box only apply to uses of this product that are covered by the Worker Protection Standard.Do not enter or allow worker entry into treated areas during the restricted-entry interval (REI) of 4 hours. Exception: If the product is soil injected or soil incorporated, the Worker Protection Standard, under certain circumstances, allows workers to enter the treated area if there will be no contact with anything that has been treated.PPE required for early entry to treated areas that is permitted under the Worker Protection Standard and that involves contact with anything that has been treated, such as plants, soil or water is:

Long-sleeved shirt and long pantsWaterproof glovesShoes plus socksDust/mist filtering respirator with MSHA/NIOSH-approval number prefix

TC-21C or a NIOSH-approved respirator with any approval number prefix N-95, R-95 or P-95 or HE filter.

Products for Soil Arthropod Microbial Control

• Microbial ControlMicrobial Control– Bacillus Bacillus

(Paenibacillus) (Paenibacillus) popilliaepopilliae

– Bacillus Bacillus thuringiensis thuringiensis var. israelensis var. israelensis

– BeauveriaBeauveria spp. spp.

Suppression of Plant DiseaseSuppression of Plant Disease

Induction of Systemic Acquired Resistance

SystemicAcquiredResistance

Plant GrowthPromotingRhizobacteria Compos

tVetch MulchOther

Microbes

Suppression of Cucumber Beetles/Corn Rootworms and Bacterial Wilt

• Beetles feed on cucurbits, prefer plants high in bitter cucurbitacin

• PGPR reduce bitter cucurbitacins

• Less attractive to beetles• Less damage and bacterial

wilt

Amending Soil with Amending Soil with

Compost to Increase Activity Compost to Increase Activity

of Beneficial Microbes that of Beneficial Microbes that

Suppress Pathogens or Induce Suppress Pathogens or Induce

Resistance Resistance

Organic - Farm - Cannery-waste CompostOrganic - Farm - Cannery-waste Compost

Anthracnose reduced in 1998 Anthracnose reduced in 1998 (high rate)(high rate)

Conventional - Plots - Yard-waste CompostConventional - Plots - Yard-waste Compost

Anthracnose incidence NOT affectedAnthracnose incidence NOT affected

Bacterial spot reduced in 1997.Bacterial spot reduced in 1997.

Foliar disease severity increased.Foliar disease severity increased.

Research conducted at OSU, 1997-1998Research conducted at OSU, 1997-1998

Compost Soil Amendment - TomatoCompost Soil Amendment - Tomato

Phytophthora Blight

Amending soil with compost

20 dry tons/A = 40-45 wet tons/A.20 dry tons/A = 40-45 wet tons/A.

Spread and incorporated in June.Spread and incorporated in June.

2001. Brewery-waste compost. Pumpkin.2001. Brewery-waste compost. Pumpkin.

2002. Yard-waste compost. Sweet corn.2002. Yard-waste compost. Sweet corn.

2003. Yard-waste compost. Snap bean.2003. Yard-waste compost. Snap bean.

2004. Yard-waste compost. Pumpkin.2004. Yard-waste compost. Pumpkin.

Annual Compost Soil AmendmentsAnnual Compost Soil Amendments

NontreatedNontreated 7070 aa (13 - 99)(13 - 99) 2020 aa (4 - 41)(4 - 41)

Compost *Compost * 8181 aa (4 - 100)(4 - 100) 1212 aa (0 - 48)(0 - 48)

TreatmentTreatment % Blighted% Blighted # Good Fruit# Good Fruit(17 Sept 2001)(17 Sept 2001) (20 Sept 2001)(20 Sept 2001)

Efficacy of Brewery-Waste Compost Efficacy of Brewery-Waste Compost for Phytophthora Blight in Pumpkinfor Phytophthora Blight in Pumpkin

* 45 wet tons/A (20 dry tons/A) spread on 5 June 2001, then * 45 wet tons/A (20 dry tons/A) spread on 5 June 2001, then incorporated. Pumpkins direct-seeded on 28 June 2001.incorporated. Pumpkins direct-seeded on 28 June 2001.

NontreatedNontreated 3.23.2 3.43.4 2.42.4

Compost *Compost * 4.04.0 5.95.9 3.93.9

Organic Matter (std Organic Matter (std Soil Analysis) Soil Analysis)

TreatmentTreatment June 2003June 2003 Sept 2004Sept 2004 May 2005May 2005

* 40-45 wet tons/A (20 dry tons/A) applied June 2001, 2002, 2003, 2004.* 40-45 wet tons/A (20 dry tons/A) applied June 2001, 2002, 2003, 2004.

Soil sampled before compost amendment.Soil sampled before compost amendment.

Rotation: pumpkin, sweet corn, snap bean, pumpkin.Rotation: pumpkin, sweet corn, snap bean, pumpkin.

Impact of Compost Amendments, 2001 - 2004Impact of Compost Amendments, 2001 - 2004

NontreatedNontreated 0.230.23 0.100.10 0.030.03

Compost *Compost * 0.430.43 0.470.47 0.280.28

Particulate Organic Matter (2003)Particulate Organic Matter (2003)

TreatmentTreatment <250 <250 mm 250 250 m-2 mmm-2 mm > 2 mm> 2 mm

* 40-45 wet tons/A (20 dry tons/A) applied June 2001, 2002, 2003, 2004.* 40-45 wet tons/A (20 dry tons/A) applied June 2001, 2002, 2003, 2004.

Rotation: pumpkin, sweet corn, snap bean, pumpkin.Rotation: pumpkin, sweet corn, snap bean, pumpkin.

Impact of Compost Amendments, 2001 - 2004Impact of Compost Amendments, 2001 - 2004

Compost-amended Plots

7/28/04

NontreatedNontreated 88 aa (0 - 38)(0 - 38) 2323 aa (0 - 67)(0 - 67)

Compost *Compost * 44 aa (0 - 17)(0 - 17) 2020 aa (2 - 48)(2 - 48)

% Fruit with Phytophthora% Fruit with Phytophthora

TreatmentTreatment 13 Oct 13 Oct 1 Nov 1 Nov

Efficacy - 4 Years of Compost - PhytophthoraEfficacy - 4 Years of Compost - Phytophthora

* 40 wet tons/A (20 dry tons/A) applied June 2001, 2002, 2003, * 40 wet tons/A (20 dry tons/A) applied June 2001, 2002, 2003, 2004.2004.

Rotation: pumpkin, sweet corn, snap bean, pumpkin.Rotation: pumpkin, sweet corn, snap bean, pumpkin.

Mycorrhizal InoculantsMycorrhizal InoculantsArbuscular mycorrhizae akaArbuscular mycorrhizae aka

endomycorrhizal fungiendomycorrhizal fungi

Natural symbiotic fungi - healthy rootsNatural symbiotic fungi - healthy roots

Root system larger and more activeRoot system larger and more active

Plants tolerate root pathogensPlants tolerate root pathogens

Reduced growth of pathogensReduced growth of pathogens

Increased host resistance?Increased host resistance?

Competition for resources?Competition for resources?

Research in OH + MD:Research in OH + MD:

suppression ofsuppression ofFusarium fruit rot, Fusarium fruit rot, gummy stem blight,gummy stem blight,Microdochium blight.Microdochium blight.

Also powdery mildew.Also powdery mildew.

Using Cover Crops for Control Using Cover Crops for Control of Fruit Rot in Pumpkinof Fruit Rot in Pumpkin

Hairy vetch and/or rye.Hairy vetch and/or rye.

5/12 plastic laid

7/28/04

5/14 Dutch white clover seeded