Fusarium Dieback Update Presented by: Ken Melban, Vice President Industry Affairs,California Avocado Commission Credits: Tom Bellamore, President Dr. Tim Spann, Research Program Director
Commission PSHB Research & Outreach Funding Researcher Project Dates Amount Eskalen & Stouthamer Paine Stouthamer Eskalen Eskalen & Stouthamer Eskalen Early Detection & occurrence of Fusarium dieback on avocados in CA 4/1/12 10/31/12 Biology & control of Euwallacea sp. the vector of Fusarium dieback disease in CA avocados Identification of shot hole borers and determination of the species of Euwallacea affecting avocados in CA Identification and management of Fusarium dieback disease on avocados in California 8/1/12 4/30/15 11/1/12 10/31/14 11/1/12 10/31/14 PSHB & Fusarium dieback monitoring 4/1/13 10/31/15 Assessment of fungicides and biocontrol agents to control pathogenic fungal species transmitted by the PSHB 11/1/13 10/31/15 Stouthamer Biocontrol of PSHB 11/1/14 10/31/15 Stouthamer Trapping optimization and development of attract and kill strategy for the PSHB in avocado 11/1/14 10/31/15 Morse & Byrne Systemic pesticide research for the management of PSHB on avocado 11/1/14 10/31/16 Eskalen & Atkinson Polyphagous Shot Hole Borer Risk assessment & epidemiology of PSHB and Fusarium dieback throughout commercial avocado groves in CA 5/1/15 10/31/18 $100,000 $325,502 $27,844 $94,588 $166,405 $151,426 $50,000 $165,152 $204,508 $417,600 TOTAL: $1,703,025
History, Movement & Monitoring in California
Situation in California First detected in CA in 2003 in Whittier Narrows Misidentified as Euwallacea fornicatus (Tea Shot Hole Borer) Since then caught a couple of times in CDFA traps in LA County (Continued)
Situation in California Caused death of large number of Box Elder street trees in Long Beach in 2011 Problem not recognized until February 2012 when it was found on a backyard avocado tree in South Gate
Plant Host Range Number of Tree Species Attacked by Beetle Number of Tree Species Infected by Fungus http://eskalenlab.ucr.edu/ 303 138 Number of tree families 62 Number of Reproductive Hosts 37 Number of Agricultural Crops 13 Number of Native Plants 15 Known reproductive hosts: 1. Box elder (Acer negundo)* 2. Big leaf maple (Acer macrophyllum)* 3. Evergreen Maple (Acer paxii) 4. Trident maple (Acer buergerianum) 5 Japanese maple (Acer palmatum) 6. Castor bean (Ricinus communis) 7. California sycamore (Platanus racemosa)* 8. Mexican sycamore (Platanus mexicana) 9. Red willow (Salix laevigata)* 10. Avocado (Persea americana) 11. Mimosa (Albizia julibrissin) 12. English Oak (Quercus robur) 13. Coast live oak (Quercus agrifolia)* 14. London plane tree (Platanus x acerifolia) 15.Cottonwood (Populus fremontii)* 16. Black cottonwood (Populus trichocarpa)* 17. White Alder (Alnus rhambifolia)* 18.Titoki (Alectryon excelsus) 19. Engelmann oak (Quercus engelmannii)* 20. Cork Oak (Quecus suber) 21. Valley oak (Quercua lobata)* 22. Coral tree (Erythrina corallodendon) 23. Blue palo verde (Cercidium floridum)* 24. Palo verde (Parkinsonia aculeata) 25. Moreton Bay Chestnut (Castanospermum australe) 26. Brea (Cercidium sonorae) 27. Mesquite (Prosopis articulata)* 28. Weeping willow (Salix babylonica) 29. Chinese holly (Ilex cornuta) 30. Camelia (Camellia semiserrata) 31. Acacia (Acacia spp.) 32. Liquidambar (Liquidambar styraciflua) 33. Red Flowering Gum (Eucalyptus ficifolia) 34. Japanese wisteria (Wisteria floribunda) 35. Goodding's black willow (Salix gooddingii)* 36. Tree of heaven (Alianthus altissima) 37. Kurrajong (Brachychiton populneus)
Urban Landscape at Risk Polyphagous Shot Hole Borer (Continued)
Urban Landscape at Risk Polyphagous Shot Hole Borer
Known Distribution Dec 2012
Known Distribution Dec 2013
Known Distribution Dec 2014 August 2014 San Diego County first commercial avocado grove find 15 groves currently infested
PSHB Monitoring Grid CAC has developed an extensive grid of traps to identify new PSHB locations San Diego/Riverside Counties 64 traps Primarily located in avocado groves (Continued)
PSHB Monitoring Grid Ventura County 50 traps Santa Barbara County 5 traps San Luis Obispo County 5 traps Sentinel traps in these three counties deployed in high-risk areas (Campgrounds, greenwaste locations, nurseries, some avocado groves) Polyphagous Shot Hole Borer
PSHB Monitoring Grid Polyphagous Shot Hole Borer http://eskalenlab.ucr.edu/distribution.html
PSHB/FD Pesticide & Fungicide Trials Efficacy trials in infested Escondido grove (field lab), Pine Tree Ranch Possibly pursuing two Section 18s (emergency registrations) Tilt (propiconazole) possible FD preventative tree injection labor intensive Hero (bifenthrin + zeta-cypermethrin) (AI in mustang) may reduce beetle levels/level of new attack foliar treatment will require multiple applications (up to 5)
Research Activities
Polyphagous Shot Hole Borer Research has focused on: Beetle identification Geographic distribution/subpopulations Basic biology of the beetle Identification of Fusarium and other fungi Pesticide and fungicide trials Biocontrol and non-chemical control Trap and lure development
Beetle Identification Polyphagous Shot Hole Borer Commonly referred to in California as the Polyphagous Shot Hole Borer Genetic analysis led by Dr. Richard Stouthamer revealed a 14% difference between TSHB and PSHB A new species as yet unofficially named Euwallacea sp. (near fornicatus) Originated from Southeast Asia, likely Vietnam (Southern China) Spring 2014, a new population discovered in San Diego County A different, but closely related species, from the L.A. population of the beetle Originated from Taiwan
PSHB Biology Polyphagous Shot Hole Borer Some information based on the closely related Tea Shot Hole Borer Ambrosia beetles symbiotic relationship with fungi Self-sufficient Sex ratio is heavily skewed to females Females emerge from galleries already mated Single female can start a new population (Continued)
PSHB Biology Polyphagous Shot Hole Borer Some information based on the closely related Tea Shot Hole Borer Newly emerged beetles either re-infest the same tree or disperse to a new host Disperse vs. stay trigger unknown Host tree health, beetle population? Based on TSHB Generally fly in the afternoon, temp. > 68 F Can fly 1.3-2 ft/s for up to 1 hr With favorable winds maybe fly up to 8 miles per generation Probably much less typically
Symbiotic Fungi Different Fungi for L.A. and San Diego Beetles L.A. beetle population carries three symbiotic fungi Fusarium euwallaceae Graphium sp. Acremonium sp. San Diego population carries two symbiotic fungi Fusarium sp. Graphium sp. (continued)
Symbiotic Fungi Different Fungi for L.A. and San Diego Beetles L.A., Orange, Riverside, San Bernardino Counties Fusarium euwallaceae Graphium sp. Sarocladium sp. San Diego County
Pesticide Trials Borrowing heavily from work in Florida on redbay ambrosia beetle Early California work done on non-avocado hosts Neonicotinoids (imidacloprid, etc.) not highly effective, poor activity against beetles (Bayer CropScience research) Most registered pesticides on avocado unlikely to have enough persistence to be effective IR-4 process for new materials is slow typically 4-5 years (continued)
Pesticide Trials Borrowing heavily from work in Florida on redbay ambrosia beetle Early California work done on non-avocado hosts Trunk injection/infusion trials underway at Pine Tree Ranch Likely another year or more before sufficient data for a Section 18 Trunk sprays Bifenthrin most promising Hero EW (bifenthrin + zeta-cypermethrin; FMC supports) IR-4 program already underway for avocado, sufficient residue data for a Section 18 5 applications, as close as every 15 days Bioassays underway to develop efficacy data to prepare a Section 18 request
Fungicide Trials Sequential progression from laboratory assays greenhouse trials field trials Initially screened > 15 fungicides in laboratory assays Reduced to about 5 for greenhouse trials Reduced to 3 with and without pesticides for field trials Tilt (propiconazole) moving forward for Section 18 Already in the IR-4 program Florida was successful in receiving a Section 18 for Laurel Wilt Applied as an infusion to the base of the trunk, or injection into trunk and major limbs Best applied PRIOR to infestation (i.e., a preventative) Efficacy is slow (up to several months to move throughout tree), but persistent (possibly up to 2 years)
Biological Control Vietnam & Taiwan Polyphagous Shot Hole Borer Vietnam Stouthamer and Eskalen visited in April 2014 & 2015 Native range of L.A. beetle population Established cooperative research agreement through USDA Farm Bill with Vietnamese entomologists Established mass rearing of beetle Collected about 450 samples including predaceous thrips, several species of mites, predaceous beetle larvae and fly larvae Cooperators have been identifying the species collected and determining if they hold potential as natural enemies (Continued)
Biological Control Vietnam & Taiwan Polyphagous Shot Hole Borer Taiwan Stouthamer and Eskalen visited in April/May 2015 Native range of San Diego beetle population
Biological Control Endemic & Commercially Available Polyphagous Shot Hole Borer Eskalen has been looking for fungi and the avocado trees that may be antagonistic to Fusarium species 32 total bacterial and fungal isolates screened 13 bacterial isolates inhibited growth of Fusarium euwallaceae in vitro Identified as Bacillus species No Inhibition Inhibition Photo from: Dr. Akif Eskalen, UC Riverside (Continued)
Trap & Lure Technology In Fall 2014 an effective lure for PSHB was found Quercivorol Original formulation 3250 expensive and difficult to produce Has been replaced with 3361 as effective or slightly better, easier to produce in large quantities Trap types and placement are currently being tested 12 funnel vs. 4 funnel vs. vane trap Polyphagous Shot Hole Borer (Continued)
Trap & Lure Technology In Fall 2014 an effective lure for PSHB was found Quercivorol Trap efficiency affected by many factors Temperature beetle emergence and when they fly Wind dispersion of lure smell, distance beetles can fly Trap location relative to infested trees Trap location in landscape All factors currently being evaluated Trap-and-kill and trap-and-infect strategies Polyphagous Shot Hole Borer
Thank You Ken Melban, Vice President Industry Affairs Tom Bellamore, President Dr. Tim Spann, Research Program Director California Avocado Commission