What are Mycorrhizal Fungi?

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

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

3. 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”

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

5. Christine Engelbrecht

6. 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

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

9. 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 poplaramong others

10. Mark Brundrett

12. 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

13. Mark Brundrett

14. Mark Brundrett

15. 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

16. 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

17. 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

18. Benefits of Mycorrhizae Inoculation • Improves establishment rates • Enhances phosphorus acquisition • Increases solubility of normally unavailable forms of phosphorus

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

20. 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

21. 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

22. 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

23. 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

24. 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

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

26. 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.

27. 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

28. Questions?

29. 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

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

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