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Managing Soilborne Plant Diseases and Arthropod Pests of Vegetables Meg McGrath and Mary Barbercheck.

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Presentation on theme: "Managing Soilborne Plant Diseases and Arthropod Pests of Vegetables Meg McGrath and Mary Barbercheck."— Presentation transcript:

1 Managing Soilborne Plant Diseases and Arthropod Pests of Vegetables Meg McGrath and Mary Barbercheck

2 Crop Rotations Reduce Pest Habitat Provide Beneficial Habitat Know Your Pest Minimal Pesticide Use Above-Ground Diversity to Favor Beneficials Pest and Disease Suppression Minimal Use of Synthetic Pesticides & Fertilizers Minimize Tillage to Conserve OM Crop Rotations Add Organic Matter Below-Ground Diversity Healthy Soil

3 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 & amoeba One to several hundred ciliates  Nematodes 10 to 20 bacterial feeders and a few fungal feeders  ArthropodsUp to 100  Earthworms5 or more

4 Ecosystem Services Provided by Soil Organisms Decomposition and nutrient cycling Carbon sequestration Maintenance of plant diversity Bioremediation Biological control of pests

5

6 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 quiescent stageAs specialized, protective, dormant or quiescent stage –(e.g., fungal sclerotia, nematode cysts, pupae) In insect or nematode vectors - pathogensIn insect or nematode vectors - pathogens As saprophytes or by omnivoryAs saprophytes or by omnivory

7 White Mold

8 Biocontrol of Soilborne Pests Mechanisms Direct action on pathogens + invertebrate pests:Direct action on pathogens + invertebrate pests: –Competition (plant pathogens) –Antagonism (e.g., antibiotic production) –Predation –Parasitism and disease Indirect (e.g., through host effect)Indirect (e.g., through host effect) –Induced resistance –Growth promotion

9 Biocontrol of Pests in Soil Approaches ConservationConservation AugmentativeAugmentative InundativeInundative ClassicalClassical

10 Biocontrol of Pests in Soil Conservation Improve environment for beneficial organisms in fieldImprove environment for beneficial organisms in field –e.g., increase soil organic matter, minimize tillage, conserve surface residues –Can favor some pathogens and pests!

11 Conservation Biocontrol Microorganisms in Soil BacteriaActinomycetes FungiMycorrhizae

12 Conservation Biocontrol Predatory Microarthropods in Soil Mesostigmatid mite Japygid Ground beetle and Rove beetle larvae Centipede Pseudoscorpion

13 Conservation Biocontrol Soil Surface Beneficials Ground and Rove Beetles

14 Conservation Biocontrol Soil Surface Spiders

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

16 Biocontrol of Pests in Soil Augmentation Apply products or materials (e.g., compost) to augment beneficial organisms already presentApply products or materials (e.g., compost) to augment beneficial organisms already present This approach builds populations of organisms already present but in numbers too low for effective pest managementThis approach builds populations of organisms already present but in numbers too low for effective pest management

17 Understory Management in Apples (Mathews et al. 2002) a b b b

18 a b b b

19 Biocontrol of Pests in Soil Inundation Apply products or materials in same manner as a pesticideApply products or materials in same manner as a pesticide This approach introduces large numbers of organisms for relatively fast-acting controlThis approach introduces large numbers of organisms for relatively fast-acting control

20 Products for Soil Arthropod Biological Control Steinernema spp. Steinernema spp. Heterorhabditis spp. Heterorhabditis spp. Hypoaspis miles (predatory soil mites) Hypoaspis miles (predatory soil mites) Atheta coriaria (generalist predator) Atheta coriaria (generalist predator)

21 Signs and symptoms of nematode infection

22 Biocontrol of Pests in Soil Classical Introduce a non-native organisms to control a non-native pestIntroduce a non-native organisms to control a non-native pest Intention is establishment of beneficial organism for long-term, low input pest managementIntention is establishment of beneficial organism for long-term, low input pest management IntroducebeneficialEstablishment and control

23 Biocontrol of Pests in Soil Some Challenges Soil abiotic or biotic environment may not support sufficient numbers of beneficials for controlSoil abiotic or biotic environment may not support sufficient numbers of beneficials for control Pest not present or in adequate number to support beneficialsPest not present or in adequate number to support beneficials Some biocontrols are very specific. Others are generalistsSome biocontrols are very specific. Others are generalists Environmental conditions affect efficacy; performance can be inconsistentEnvironmental conditions affect efficacy; performance can be inconsistent

24 Biocontrol of Pests in Soil Regulations Microbial and chemical products claiming control must be registered as pesticides with US EPA. Must be registered in state.Microbial and chemical products claiming control must be registered as pesticides with US EPA. Must be registered in state. Beneficial macro-organisms exempt from EPA registrationBeneficial macro-organisms exempt from EPA registration Efficacy data not required for registrationEfficacy data not required for registration Safety to environment + nontarget organisms is focus of registrationSafety to environment + nontarget organisms is focus of registration

25 Biocontrol of Pests in Soil Regulations Efficacy data from replicated experiments often lacking, especially for vegetable uses!!Efficacy data from replicated experiments often lacking, especially for vegetable uses!! EPA/IR-4 Biopesticide Demonstration Grant ProgramEPA/IR-4 Biopesticide Demonstration Grant Program

26 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.

27 Efficacy - Biocontrol Products - Greenhouse Ornamentals # Experiments # Experiments EffectiveIneffective Companion03 Deny01 Mycostop04 PlantShield04 Primastop13 Rootshield311 SoilGard26 Pathogens: Pythium, Rhizoctonia, Fusarium, Thielaviopsis

28 Mycostop Biofungicide Label Contents Keep Out of Reach of Children CAUTION PRECAUTIONARY 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.

29 AGRICULTURAL USE REQUIREMENTS Use 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 pants Waterproof gloves Shoes plus socks Dust/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.

30 Products for Soil Arthropod Microbial Control Microbial ControlMicrobial Control –Bacillus (Paenibacillus) popilliae –Bacillus thuringiensis var. israelensis –Beauveria spp.

31 Suppression of Plant Disease Suppression of Plant Disease Induction of Systemic Acquired Resistance Systemic Acquired Resistance Plant Growth Promoting Rhizobacteria Compost Vetch Mulch Other Microbes

32 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

33 Amending Soil with Compost to Increase Activity of Beneficial Microbes that Suppress Pathogens or Induce Resistance

34 Organic - Farm - Cannery-waste Compost Anthracnose reduced in 1998 (high rate) Conventional - Plots - Yard-waste Compost Anthracnose incidence NOT affected Bacterial spot reduced in 1997. Foliar disease severity increased. Research conducted at OSU, 1997-1998 Compost Soil Amendment - Tomato

35 Phytophthora Blight

36 Amending soil with compost

37 20 dry tons/A = 40-45 wet tons/A. Spread and incorporated in June. 2001. Brewery-waste compost. Pumpkin. 2002. Yard-waste compost. Sweet corn. 2003. Yard-waste compost. Snap bean. 2004. Yard-waste compost. Pumpkin. Annual Compost Soil Amendments

38 Nontreated70a(13 - 99)20a(4 - 41) Compost *81a(4 - 100)12a(0 - 48) Treatment % Blighted# Good Fruit (17 Sept 2001)(20 Sept 2001) Efficacy of Brewery-Waste Compost for Phytophthora Blight in Pumpkin * 45 wet tons/A (20 dry tons/A) spread on 5 June 2001, then incorporated. Pumpkins direct-seeded on 28 June 2001.

39 Nontreated3.23.42.4 Compost *4.05.93.9 Organic Matter (std Soil Analysis) Organic Matter (std Soil Analysis) Treatment June 2003Sept 2004May 2005 * 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 - 2004

40 Nontreated0.230.100.03 Compost *0.430.470.28 Particulate Organic Matter (2003) Particulate Organic Matter (2003) Treatment 2 mm * 40-45 wet tons/A (20 dry tons/A) applied June 2001, 2002, 2003, 2004. Rotation: pumpkin, sweet corn, snap bean, pumpkin. Impact of Compost Amendments, 2001 - 2004

41 Compost-amended Plots 7/28/04

42 Nontreated8a(0 - 38)23a(0 - 67) Compost *4a(0 - 17)20a(2 - 48) % Fruit with Phytophthora % Fruit with Phytophthora Treatment 13 Oct 1 Nov Efficacy - 4 Years of Compost - Phytophthora * 40 wet tons/A (20 dry tons/A) applied June 2001, 2002, 2003, 2004. Rotation: pumpkin, sweet corn, snap bean, pumpkin.

43 Mycorrhizal Inoculants Arbuscular mycorrhizae aka endomycorrhizal fungi Natural symbiotic fungi - healthy roots Root system larger and more active Plants tolerate root pathogens Reduced growth of pathogens Increased host resistance? Competition for resources?

44 Research in OH + MD: suppression of Fusarium fruit rot, gummy stem blight, Microdochium blight. Also powdery mildew. Research in OH + MD: suppression of Fusarium fruit rot, gummy stem blight, Microdochium blight. Also powdery mildew. Using Cover Crops for Control of Fruit Rot in Pumpkin Hairy vetch and/or rye.

45 5/12 plastic laid 7/28/04 5/14 Dutch white clover seeded


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