Armillaria Root Rot

1. Armillaria Root Rot I selected this because My property had many trees remove but roots where left I have seen symptoms in one small area of Vineyard It’s prevalent in your area of California

2. General information It’s a fungus, loves cool moist soil • Infects woody roots & trunk base • Effects large variationof plants • Difficult to stop • Slow death of the plant BRE Properties, Inc.

3. Signs & Symptoms • First sign can be Aug • Short weak shoots • Small clusters • Poor ripening • Low NPK in Petiole lab tests Mushrooms Fully bloom

4. Signs & Symptoms • Leaves turn red • Wilted leaves • Early defoliation • Death is normally during dormancy

5. Sign & symptoms • Mushrooms – needs moisture. Doesn’t act as disease spreader • Near former diseased trees • Vine productivity slows and die 2-4 years

6. Signs, Symptoms & Diagnose • Base of trunk just under the surface. • White Mycelial under the bark near • Light brown spongy wood -

7. Signs, Symptoms & Diagnose • rhizomorphs very rare in vines • Can spread to vine planted near diseased areas under ground • Will decrease in severity as move away from infected center • This is one way of control

8. Disease cycle • Fungus is present in soil as part of old tree roots & stumps • Vine roots come in contact with infected area • These are colonized and become inoculum and released as spores • Vine tissues are attacked and spreads to root collar • Trunk is girdled and eventually incapable of supporting vine

9. Management – preplanting • Avoiding land with history of trees or disease • Ripping and removal of roots • Fumigation chemicals • Stay updated via UCDavis options

10. Management post plant Several options • ID the smaller infected area and don’t plant • Keep area dry, drips lines • Monitor and know your land history

11. Early season • In spring clear soil around base of vine expose upper roots to air out and dry 12-16 inches. • This can be very effective and can be perminate if done early life of vine

12. More on Controls Success of chemicals is dependent on drainage, site slope and site orientation…. Dry soil Best done before planting or in dormant season Biological Microbial control is showing promise in the form of a bacterial strain that inhabits the pathogen development Resistant roots stocking is being developed, but not yet on market

13. Treatments – Sept - Nov • When choosing a pesticide, consider the environmental impact. • METHYL BROMIDE – see label rates  • COMMENTS: Preplant treatment. May only be used under a Critical Use Exemption. Fumigants such as methyl bromide are a source of volatile organic compounds (VOCs) but are not reactive with other air contaminants that form ozone: methyl bromide depletes ozone. Fumigate only as a last resort when other management strategies have not been successful or are not available. • METAM SODIUM - (Vapam, etc.) • COMMENTS: Apply in winter when soil moisture is high. Fumigants such as metam sodium are a source of volatile organic compounds (VOCs) but are minimally reactive with other air contaminants that form ozone. Fumigate only as a last resort when other management strategies have not been successful or are not available.

14. My question for the Final • The Armillaria fungus thrives best in what type of soil a – Hot wet soil b – Cool moist soil c. – Dry warm soil d.- Dry cool soil

15. The End • Any questions ? • Next presenter please