What are Mycorrhizal Fungi? Mark Howieson Product Development Specialist Becker Underwood, Inc.

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

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”

Common Occurrence Most common association between microorganisms and higher plants –Early fossilized plants were mycorrhizal –95% of all plant families are mycorrhizal

Christine Engelbrecht

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

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

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

Mark Brundrett

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

Mark Brundrett

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

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 weeks before and after inoculation

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

Benefits of Mycorrhizae Inoculation Improves establishment rates –Enhances phosphorus acquisition –Increases solubility of normally unavailable forms of phosphorus

Benefits of Mycorrhizae Inoculation Enhances drought tolerance –Mycorrhizae improves water uptake efficiency –Increases below ground surface area for water absorption

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

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

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

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

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

Quality-Tested Inoculum INVAM at West Virginia University –Independent laboratory analysis –Verifies viability and infectivity of inoculum The only certified inoculum in the industry

Mycorrhizal colonization of Ponderosa pine roots by Becker-Underwood Tree Transplant and Tree Root Dip inoculants in tests conducted by Mycorrhizal Applications, Grant’s Pass, OR in 1998.

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

Questions?

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

Phosphorus Response Curve Adapted from Jasper et al Cassia pruinosa

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