What are Mycorrhizal Fungi?

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What are Mycorrhizal Fungi?

• Mark Howieson
• Product Development Specialist
• Becker Underwood, Inc.

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Discussion Points

• Introduction to mycorrhizae
• Reasons to inoculate
• Benefits of mycorrhizal fungi inoculation
• Mycorrhizae products available from Becker
  Underwood

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What are Mycorrhizae?

• A mutually beneficial association between a
  fungus and a plant
• Fungus colonizes root of host plant
• Plant provides fungus with food in return for
  increased nutrient absorption from soil
• Greek origin meaning fungus root

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Common Occurrence

• Most common association between microorganisms
  and higher plants
• Early fossilized plants were mycorrhizal
• 95 of all plant families are mycorrhizal

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Christine Engelbrecht
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Enhance Nutrient and Water Uptake

• Increases soil volume accessible to plants
• Improved absorption of immobile soil nutrients
• Greater efficiency of water uptake
• Facilitates uptake from nutrient pools not
  normally available to plants
• Phosphorus often is in forms not readily absorbed
  by plant roots

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Types of Mycorrhizae

• Endomycorrhizae
• Most common with herbaceous plants but also
  associated with some woody plants
• Ectomycorrhizae
• Occur mainly on roots of woody plants

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Endomycorrhizae

• Also known as vesicular-arbuscular mycorrhiza
• Develop arbuscules and vesicles within root
  cortical cells
• Arbuscules are where carbohydrates and nutrients
  are exchanged
• Vesicles are used as storage organs
• Common in herbaceous plants
• Form associations with maple, sycamore, ash, gum,
  walnut, cypress, and poplar among others

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Mark Brundrett
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Ectomycorrhizae

• Fungi grow between root cortical cells
• Form a mantle that covers the root surface
• Roots develop a swollen appearance
• Mantle acts as a barrier to pathogens
• May develop above-ground fruiting bodies
• Mushrooms and puffballs
• Common in pine, spruce, fir, beech, eucalyptus,
  alder, oak, and hickory

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Mark Brundrett
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Mark Brundrett
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Reasons to Inoculate

• Mycorrhizal fungi are present in almost all soils
• Intensive management practices limit viability
  and infectivity of native mycorrhizal fungi
• Excessive applications of chemical fertilizers
  and pesticides

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Fungicides and Mycorrhizal Fungi

• Label usage rates and application methods
  (spray/injection) normally has no effect on
  mycorrhizal fungi
• Metabolized by soil microbes
• Drenches/Soil Injection may have detrimental
  effects
• General rule avoid use of fungicides 2 - 3 weeks
  before and after inoculation

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Reasons to Inoculate

• Severe soil disturbances like erosion, tillage,
  compaction
• Often absent in sterilized or soil-less potting
  media
• Non-native transplants grown in soil and
  climactic conditions different from the areas
  where they are planted
• Plants established in areas prone to
  environmental stresses

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Benefits of Mycorrhizae Inoculation

• Improves establishment rates
• Enhances phosphorus acquisition
• Increases solubility of normally unavailable
  forms of phosphorus

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Benefits of Mycorrhizae Inoculation

• Enhances drought tolerance
• Mycorrhizae improves water uptake efficiency
• Increases below ground surface area for water
  absorption

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Benefits of Mycorrhizae Inoculation

• Decreases transplant shock and increases survival
  and growth in the field
• Transplant success depends on how quickly a plant
  can reestablish its root system
• Mycorrhizal fungi rapidly develop below ground
  surface area for nutrient and water uptake

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Rhizanova Tree Injectable

• Ideal for newly planted or young non-coniferous
  trees
• Contains a blend of endo- and ectomycorrhizal
  fungi combined with humic substances
• Applied with professional soil injection
  equipment

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Rhizanova Pt Tree Injectable

• Beneficial for newly planted or young coniferous
  trees
• Blend of multiple strains of ectomycorrhizal
  fungi combined with humic substances
• Applied with professional soil injection
  equipment

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Rhizanova Tree Transplant

• A dry mix ideal for most transplanting
  applications
• Formulated with a blend of endo- and
  ectomycorrhizae
• Water absorbing polymer
• Organic fertilizer and humic acid
• Mixed into backfill or incorporated into potting
  media at planting

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Advantages of Rhizanova

• Emphasis on quality of inoculum
• Becker-Underwood is an ISO 9001 registered
  company
• Species selected for effectiveness with the
  broadest range of plants
• No unnecessary amendments
• High rates of phosphorus fertilizers

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Quality-Tested Inoculum

• INVAM at West Virginia University
• Independent laboratory analysis
• Verifies viability and infectivity of inoculum
• The only certified inoculum in the industry

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Mycorrhizal colonization of Ponderosa pine roots
by Becker-Underwood Tree Transplant and Tree Root
Dip inoculants in tests conducted by Mycorrhizal
Applications, Grants Pass, OR in 1998.
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Take Home Messages

• Mycorrhizae improve plant growth
• Increase supply of nutrients to plant
• Enhance water uptake efficiency
• Benefits of inoculating with mycorrhizal fungi
• Improved plant establishment rates
• Increased drought resistance
• Decreased transplant shock and improved survival

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Questions?
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Host Plants

• Endomycorrhizae
• Acacia, Ash, Bay, Boxelder, Buckeye, Cedar,
  Chokeberry, Cherry, Cottonwood, Crabapple,
  Cypress, Dogwood, Elm, Ginkgo, Gum, Hackberry,
  Hawthorn, Holly, Horsechestnut, Juniper,Locust,
  Magnolia, Maple, Mesquite, Mimosa, Mulberry,
  Palm, Persimmon, Redbud, Redwood, Russian Olive,
  Serviceberry, Sumac, Sycamore, Tupelo, Walnut,
  Yew
• Ectomycorrhizae
• Alder, Arborvitae, Aspen, Basswood, Beech, Birch,
  Chestnut, Fir, Hemlock, Hickory, Larch, Linden,
  Oak, Pecan, Pine, Spruce
• Both
• Eucalyptus, Willow, Poplar

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Phosphorus Response Curve
Cassia pruinosa
Adapted from Jasper et al. 1994
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Pesticide Interactions

• Toxic Carbamates (Maneb, Zineb), PCNB,
  Chlorothalonil (Daconil, Bravo), Triazoles
  (Bayleton), Benomyl (Benlate)
• Non-toxic Aliette, Captan, Carbendazim,
  Metalaxyl (Ridomil, Subdue)