Conservation of Insect Pathogens in Soil

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Biological Aspects of Soil Quality and Effects of
Soil Management on Soil Organisms
Mary Barbercheck Dept. of Entomology Penn State
University
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In 1 teaspoon of agricultural soil there are
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Ecosystem Services Provided by Organisms

• Decomposition and nutrient cycling
• Carbon sequestration
• Maintenance of plant diversity
• Bioremediation
• Biological control of pests

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(No Transcript)
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Elliot Coleman. 1988. Ecol. Bull. 39 23-32
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Microorganisms in Soil
Bacteria
Actinomycetes
Fungi
Mycorrhizae
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Suppression of Plant Disease
Induction of Systemic Acquired Resistance
Systemic Acquired Resistance
Plant Growth Promoting Rhizobacteria
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Cucumber Beetles/Corn Rootworms

• Prefer plants high in bitter cucurbitacin
• PGPR reduce bitter cucurbitacins in cucurbit
  plants
• Less attractive to beetles

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Natural Enemies of Pest Nematodes
Pasteuria
Hirsutella
Amoebae
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Insect Pathogens in Soil
Nematodes
Fungi
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Predatory Microarthropods in Soil
Ground beetle and Rove beetle larvae
Mesostigmatid mite
Centipede
Japygid
Pseudoscorpion
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Soil as Home
Nematode
Ants
Earthworm
Mesostigmatid Mite
Springtail
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Soil Surface Beneficials Ground and Rove Beetles

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Soil Surface Beneficials Spiders
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Some Goals of Soil Management

• Manage system for productivity and beneficial
  processes
• Improvement in abiotic and biotic properties of
  soil
• Improvement of plant health
• Conservation of beneficial organisms
• Suppression of pests

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Some Factors Affected by Tillage

• Soil Moisture
• Soil Temperature
• Range of Temperature and Moisture Fluctuations
• Surface Residue
• Soil Fauna Abundance and Diversity
• Plant Diversity
• Favors Bacteria gt Fungi

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Tillage Effects on Soil Arthropod Abundance
Diversity in Corn Goldsboro, NC

• Abundance No. of organisms/sample
• Richness No. of taxa
• Evenness 1 all taxa in similar numbers, as
  approach 0, divergence from evenness, some taxa
  more dominant

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Effects of Tillage and Cover Crops on Pest
Beneficial Arthropods in SoilPeachy et al. 2002.
Applied Soil Ecology 21 59-70
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Effects of Cover Crop Rye Managementin Reduced
Tillage CornClark et al. 1993. J. Entomol. Sci.
28 404-416
a
ab
bc
c
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Effect of Compost Type on Microbial Biomass N and
Soil ArthropodsGunadi et al. 2002. Eur. J. Soil
Biol. 38161-165
Vermicomposts
Trophic Groups
2
4
7
6
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Systems Experiment 1999-2002Microarthropods
Cumulative Average
Barbercheck, unpubl.
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Systems Experiment 1999-2002EPN EPF Cumulative
Average
Barbercheck, unpubl.
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BMP for Management of Soil Organisms

• Systems effects can arise from very complex
  direct and indirect interactions
• Minimize compaction
• Provide continuous energy (e.g., cover crops)
• Reduce tillage to maintain structure and favor
  fungal-based food webs
• Provide refuges for mobile predators
• Rotate crops to reduce pest organisms
• Reduce use of biocides

Cosmochthonius (Oribatida)
D. Walter
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Web Resources

• Soil Biodiversity Portal www.fao.org/ag/AGL/agll/s
  oilbiod/default.htm
• Soil Biology Primer
• http//www.swcs.org
• USDA Soil Quality Institute http//soils.usda.gov/
  sqi/
• Appropriate Technology Transfer for Rural
  Areashttp//www.attra.org/
• Earthworms The agriculturists friend
  http//www.eap.mcgill.ca/publications/eap6.htm

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The End
Photo by M. Greenwood
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Crop Rotations
Know Your Pest
Above-Ground Diversity to Favor Beneficials
Reduce Pest Habitat
Provide Beneficial Habitat
Minimal Pesticide Use
Pest and Disease Suppression
Healthy Plants!
Healthy Soil
Add Organic Matter
Crop Rotations
Minimize Tillage to Conserve OM
Below-Ground Diversity
Minimal Use of Synthetic Pesticides Fertilizers
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Effects of Cover Crop Rye Managementin Reduced
Tillage CornClark et al. 1993. J. Entomol. Sci.
28 404-416
a
a
a
a
a a
ab
b b
b
b
b
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Effect of Organic Mineral Fertilizers in
AlfalfaFratello et al. 1989. Agric. Ecosyst.
Envt. 27 227-239