Fusarium Dieback: Host Range, Biology, and Control Strategies in Native Vegetation in southern California A. Eskalen 1, S.C. Lynch 2, F. Na, J.S. Mayorquin 1, J.D. Carrillo 1, G.Gilbert 2, R.Stouthamer 3 1 Department of Plant Pathology and Microbiology, University of California, Riverside, CA 92521 2 Department of Environmental Studies, UC Santa Cruz 3 Department of Entomology, University of California, Riverside, CA 92521
Fusarium dieback and symbiotic fungal pathogens
Branch Dieback and Tree Wilt on different hosts A.Eskalen A.Eskalen English Oak (Quercus robur) Boxelder (Acer negundo)
Number of reproductive hosts that beetle/fungus can produce their offsprings 1. Box elder (Acer negundo)* 2. California sycamore (Platanus racemosa) * 3. London plane (Platanus x acerfolia) 4. Mexican sycamore (Platanus mexicana) 5. Red willow (Salix laevigata) * 6. Black willow (Salix gooddingii)* 7. Arroyo willow (Salix lasiolepis) * 8. Cottonwood (Populus fremontii)* 9. Black poplar (Populus nigra)* 10. Black cottonwood (Populus trichocarpa)* 11. Mimosa (Albizia julibrissin) 12. English Oak (Quercus robur) 13. Engelmann oak (Quercus engelmannii)* 14. Valley oak (Quercus lobata) 15. Palo verde (Parkinsonia aculeata) * 16. Blue palo verde (Cercidium floridum)* 17. Big leaf maple (Acer macrophyllum)* 18. Japanese maple (Acer palmatum) 19. Castorbean (Ricinus communis) 20. Canyon Live oak (Quercus chrysolepis)* 21. Avocado (Persea americana 22. Trident maple (Acer buergerianum) 23. Coast live oak (Quercus agrifolia) 24. White Alder (Alnus rhombifolia)* 25. Titoki (Alectryon excelsus) 25. Coral tree (Erythrina corallodendon) 26. Moreton Bay Chestnut (Castanospermum australe) 27. Brea (Cercidium sonorae) 28. Mesquite (Prosopis articulata)* 29. Weeping willow (Salix babylonica) 30. Chinese holly (Ilex cornuta) 31. Camelia (Camellia semiserrata) 32. Acacia (Acacia spp.) 33. Liquidambar (Liquidambar styraciflua) 34. Red Flowering Gum (Eucalyptus ficifolia) 35. Japanese wisteria (Wisteria floribunda) 36. Goodding's black willow (Salix gooddingii)* 37. Tree of heaven (Ailanthus altissima) 38. Kurrajong (Brachychiton populneus) 39. Black mission fig (Ficus carica) 40. Japanese beech (Fagus crenata) 41. Dense logwood (Xylosma congestum) 42. Mule Fat (Baccharis salicifolia)* 43. Carrotwood (Cupaniopsis anacardioides) 44. California buckeye (Aesculus californica)* 45. Kentia Palm (Howea forsteriana) 46. King Palm (Ptychosperma elegans) 47. Evergreen Maple (Acer paxii) 48. Cork Oak (Quercus suber)
Spread of the infestations PSHB KSHB 2016 http://eskalenlab.ucr.edu/distribution http://pshb.org
Current Situation in Urban Forest in California
Damage on Landscape trees
Beetle attack incidence on sycamore trees overtime 150 Mean(attacks/m^2) vs. Time Park Craig 125 attacks/m^2 Mean Attack /m 2 100 75 50 25 0 Aug '15 Sep Oct Nov Dec Jan Feb Time Mar Apr May Jun Jul Aug '16 Craig Regional Park
Can we cut infested trees at the soil level to promote sprouting as a management strategy? Sprouted Willow tree Beetle colonization at the base of the trunk
Infestation of Secondary Fungal Pathogens along with SHB/FD
Secondary fungal pathogen infestation on SHB infested Sycamore
Pesticides trials on infested sycamore trees Collaboration with John Kabashima and Tim Paine UCCE and UC Riverside
Pesticide Field Trial on Sycamore Trees Four locations throughout Orange County UC Irvine OC Parks (3 park locations) Selected host: California sycamore (Platanus racemosa) Trees classified by No/Low, Moderate and Heavy infestation levels Pesticide treatments include fungicide, insecticide, biological products and combo treatments Applications either spray or injection Monitoring/Follow up Monthly recording of beetle activity, canopy health, fungicide retention (6 and 12 months post application)
Control strategies in Native Vegetation Collaboration with Shannon Lynch and Greg Gilbert, UC Santa Cruz
Ecological modeling and adaptive management Establish monitoring plots in native vegetation to develop a prediction model for pest and disease pressure. We have already established long term monitoring plots in infested avocado orchards, the data that we have been collecting helps us develop a control strategies.
Conclusion Monitoring studies indicate that SHB is spreading in avocado orchards in California but not causing tree mortality. Some of the systemic pesticides promising to control the beetle and their symbiotic fungi on Landscape trees. The infested trees in native vegetation are sprouting, however they are being re-infested by the beetle. Secondary fungal pathogens are able to infect SHB infested trees and cause canker and dieback. Control strategies in native vegetation are underway.
California Avocado Commission U.S. Forest Service, OC Parks, UC Irvine, UC ANR, USDA Farm Bill, Arborjet, Mauget, USDA Forest Service, Cal-Fire, Huntington botanical garden and LA arboretum, UC-Mexus, Inecol, Mexico. Frederique Revenchon, Inecol, Mexico Ben Faber, Farm Advisor, Ventura County, CA\ Richard Demerjian, UC Irvine Sonia Rios, UCCE Farm Advisor, San Diego Sabrina Drill, UCCE LA and Ventura Dan Berry, Huntington Botanical Garden, Gary Bender, UCCE, Emeritus, San Diego Co. Janis Gonzales, UCCE San Diego Jim Folsom, Huntington Botanical Garden Jiri Hulcr, Univ. of Florida Kerry O Donnell, NCUR-ARS-USDA Mary Lu Arpaia, UC Riverside Kim Corella, Cal Fire Tom Smith, Cal Fire Joe Barcinas, PCA Tom Roberts, PCA Mathew Hand, PCA Linda Bellamy, Venture Susan Frankel, USDA Forest Service Tom Atkinson, University of Texas Sean Feirer, UCANR Jim Downer, UCCE Ventura Acknowledgement www.eskalenlab.ucr.edu