Dr. A. James Downer Ph.D.

Advisor
Cooperative Extension Ventura County
669 County Square Drive, #100
Ventura, CA 93003-5401
(805) 645-1458
ajdowner@ucanr.edu Create VCard

Links

Biography

BSc Cal Poly, Pomona, 1981 Botany/Ornamental Horticulture MSc Cal Poly, Pomona, 1983 Biology/Plant Pathology Ph.D. Univ. California Riverside, 1998 Plant Pathology

Education

Ph.D. Plant Pathology, UC Riverside. 1998

Specialty

Pathology of landscape ornamentals , Phytophthora Root Rot, Mulches, Potting soils, Palm horticulture, climate ready trees, arboriculture, Master Gardener Advisor.

Areas of Expertise (click to see all ANR academics with this expertise)

Bibliography

Peer Reviewed

  • Downer, A.J. and S. Swain and A. Crump (2020). Anthrcnose, UCIPM Pest Notes, Publiction # 7420.
  • Fescenko, A.; Downer, J. A., et al. (2020). Persistence of remnant boreal plants in the Chiricahua Mountains, Southern Arizona. Global Ecology and Conservation. Elsevier. 23, 1-10.
  • Downer, A.J.; Karlik, J.F. (2019). A Comparison of Two Horsechestnut Street Tree Plantings in Kiev and Pripyat, Ukraine. Open J. Forestry. 9, 255-263.
  • Downer, A.J. and I. Lacan (2019). Armillaria UC IPM Pest Notes UCANR #74171. UCANR.
  • Karlik, J.F.; Downer, A.J. (2019). Comparison of Gamma Ray Dosimeters in a Field Study in the Chernobyl Exclusion Zone. J. of Air and Waste Man. 11, 1361-1367.
  • Takeuchi, T.; Downer, A.J. (2019). Lead absorption by radish is affected by soil texture and cultivar. Open J. Soil Science. 9:4, 65-74.
  • Downer, A.J.; Faber, B. (2019). Mulches for landscapes. ANR publication #8672.
  • Downer, A.J.; Faber, B. (2019). Non-chemical prevention of Armillaria mellea infection of Peach (Prunus persica). Plant Sci. and Phytopathology. 3, 50-55.
  • Downer, A.J.; Perry, E.J. (2019). Wood Decay Fungi in the landscape. ANR publication #74109.
  • Chalker-Scott, L; Downer, J (2018). Garden myth busting for Extension Educators: Reviewing the Literature on Landscape Trees. J. of the National Assn. Ag. Agents. 11:2. https://www.nacaa.com/journal/index.php?jid=885&fbclid=IwAR3fS2iKo8ibifQEDPUrG6UlcB8n-yUgOe6xx1y56MeAcLhP6ZoUkQbUQNg
  • Downer, J. (2016). Native Diseases of California Mediterranean Forest Angiosperms.T. Paine and F. Lieutier. Springer. 529-547.
  • Neila, S.; Akef, S., et al. (2015). Carbon and nitrogen mineralization in clay loam soil amended with different composts. Advances in Applied Ag. Science 03:20-34. Advances in Applied Ag. Science. 03, 20-34.
  • Downer, A.; Howell, A., et al. (2014). "Effect of pruning on eight landscape rose varieties." Acta Horticulturae
  • Downer, A.; Hodel, D., et al. (2013). "Effect of fertilizer nitrogen source on susceptibility of five species of field grown palms to Fusarium oxysporum f. sp. carnariensis." Palms 57: 89-92.
  • Hodel, D.; Downer, A., et al. (2013). "Effect of leaf removal and tie-up on date palms transplanted in extremely hot, arid conditions." Palms 57: 72-78.
  • Hodel, D.; Downer, A., et al. (2013). "Effect of leaf removal and tie-up on water loss and estimated crop coefficients for juvenile trunkless containerized queen palms." Palms 57: 79-83.
  • Downer, A.; Hodel, D., et al. (2013). "Effect of leaf tie-up and pre-plant storage on growth and transpiration of transplanted Mexican fan palms." Palms 57: 58-63.
  • Hodel, D.; Downer, A., et al. (2013). "Effect of sand backfill on transplanted king, queen, and windmill palms." Palms 57: 63-66.
  • Bennett, P.; Bauske, E., et al. (2013). "Farmers' Market, Demonstration Gardens, and Research Projects Expand Outreach of Extension Master Gardeners." HortTechnology 23: 411-415.
  • Downer, A.; Hodel, D. (2013). "Suitability of ground palm trunk tissues as a medium for growing potted plants." Palms 57: 67-71.
  • Khiari, L.; Neila, S., et al. (2012) Control of Fusarium wilt of tomato caused by Fusarium oxysporum f.sp. lycoperscici using mixture of vegetable and Posidonia oceanica compost. Applied and Environmental Soil Science 11 DOI: 10.1155/2012/239639
  • Hodel, D.; Downer, A., et al. (2012). "Effect of container type on the nursery growth of kentia palms and king palms." Palms 56: 65-71.
  • Mayorquin, J.; Eskalen, A., et al. (2012). "First report of multiple species of the botryosphaeriaceae causing bot canker disease of Indian laurel leaf fig in California." Plant Disease 96(3): 459.
  • Corkidi, L.; Merhaut, D., et al. (2011). "Effects of Mycorrhizal colonization on nitrogen and phosphorus leaching from nursery containers." HortScience 46: 1472-1479.
  • Pittenger, D.; Downer, A., et al. (2009). "Estimating water needs of landscape palms in Mediterranean climates." HortTechnology 19: 700-704.
  • Downer, A.; Uchida, J., et al. (2009). "Lethal palm diseases common in the United States." HortTechnology 19: 710-716.
  • Downer, A.; Hodel, D., et al. (2009). "Pruning Landscape Palms." HortTechnology 19: 695-699.
  • Hodel, D.; Downer, A., et al. (2009). "Pruning Landscape Palms." HortTechnology 19: 695-699.
  • Hodel, D.; Downer, A., et al. (2009). "Transplanting Palms." HortTechnology 19: 686-689.
  • Downer, A.; Crohn, D., et al. (2008). "Survival of plant pathogens in static piles of ground green waste." Phytopathology 98: 574-554.
  • Faber, B.; Downer, A., et al. (2007). "Accuracy varies for commercially-available soil test kits analyzing nitrate nitrogen, phosphorus, potassium and pH." HortTechnology 17: 358-362.
  • Crohn, D.; Faber, B., et al. (2007). "Probabilities for survival of glassy-winged sharpshooter and olive fruit fly pests in urban yard waste piles." Bioresource Technology 99: 1425-1432.
  • Hodel, D.; Downer, A., et al. (2006). "Effect of leaf removal and tie-up on transplanted large Mexican fan palms (Washingtonia robusta)." Palms 50: 76-81.
  • Hodel, D.; Downer, A., et al. (2006). "Effect of leaf removal and tie-up on transplanted large Mexican fan palms (Washingtonia robusta)." Palms 50: 76-81.
  • Koike, S.; Daugovish, O., et al. (2006). "Sclerotinia stem and crown rot of celery, caused by Sclerotinia minor, in California." Plant Disease 90: 829.
  • Hodel, D.; Downer, A., et al. (2006). "The effect of amended backfill soils when planting five species of palms." HortTechnology 16: 457-460.
  • Daugovish, O.; Downer, A., et al. (2006). "Weed survival in yardwaste mulch." Weed Technology 21: 59-65.
  • Downer, A.; Faber, B. (2005). "Effect of Eucalyptus cladocalyx mulch on establishment of California sycamore (Platanus racemosa)." Journal of Applied Horticulture 7: 90-94.
  • Corkidi, L.; Allen, E., et al. (2005). "Effectiveness of four commercial mycorrhizal inoculants on the growth of Liquidambar styraciflua in plant nursery conditions." Journal of Environmental Horticulture 23: 72-76.
  • Dahlsten, D.; Dane, K., et al. (2005). "Imported parasitoid helps control red gum lerp psyllid." California Agriculture 59: 229-234.
  • Hodel, D.; Pittenger, D., et al. (2005). "Palm root regeneration and implications for transplanting." Journal of Arboriculture 31: 171-181.
  • Pittenger, D.; Hodel, D., et al. (2005). "Transplanting specimen palms: a review of common practices and research-based information." HortTechnology 15: 128-132.
  • Corkidi, L.; Allen, E., et al. (2004). "Assessing the infectivity of commercial mycorrhizal inoculants in plant nursery conditions." Journal of Environmental Horticulture 22: 149-154.
  • Daugovish, O.; Downer, A., et al. (2004). "Mustard-derived biofumigation for vegetable crops and strawberries." Agroindustria 3: 5-8.
  • Valenzuela-Solano, C.; Crohn, D., et al. (2004). "Nitrogen mineralization from eucalyptus yard waste mulch applied to young avocado trees." Biology and Fertility of Soils 41: 38-45.
  • Hodel, D.; Pittenger, D., et al. (2003). "Effect of Leaf removal and tie up on juvenile transplanted canary island date palms (Phoenix canariensis) and queen palms (Syagrus romanzoffiana)." Palms 47: 177-184.
  • Downer, A.; Craigmill, A., et al. (2003). "Toxic potential of oleander derived compost and vegetables grown with oleander soil amendments." Journal of Human and Veterinary Toxicology 45: 219-221.
  • Downer, A.; Faber, B., et al. (2002). "Factors affecting root rot control in mulched avocado orchards." HortTechnology 12: 601-605.
  • Dagit, R.; Downer, A. (2002). To prune or not to prune: recovery of Coast Live Oak after transplanting. 5th Oak Symposium (Proceedings), San Diego, CA, USDA Forest Service.
  • Downer, A.; Menge, J., et al. (2001). "Association of cellulytic enzyme activities in eucalyptus mulches with biological control of Phytophthora cinnamomi Rands." Phytopathology 91: 847-855.
  • Faber, B.; Downer, A., et al. (2001). "Differential effects of mulch on citrus and avocado." Acta Horticulturae 557: 303-307.
  • Downer, A.; Menge, J., et al. (2001). "Effects of cellulytic enzymes on Phytophthora cinnamomi Rands." Phytopathology 91: 839-846.
  • Downer, A.; Hodel, D. (2001). "The effect of mulching and turfgrass on growth and establishment of Syagrus romanzoffiana (Cham.) Becc., Washingtonia robusta H.Wendl. and Archontophoenix cunninhamiana (H.Wendl.)H. Wendl. & Drude in the landscape." Scientia Horticulturae 87: 85-92.
  • Dagit, R.; Downer, A. (1999). "Transplanted coast live oaks (Quercus agrifolia) in southern California." Journal of the International Oak Society 9: 145-150.
  • Downer, A. (1998). The effects of mulch on Phytophthora cinnamomi and Avocado Root Rot. Ph.D. Dissertation. University of California, Riverside, CA. 212.
  • Dagit, R.; Downer, A. (1997). Status of transplanted coast live oaks in Southern California. Symposium on Oak Woodlands: Ecology, Management and Urban Interface Issues (Proceedings), San Luis Obispo, CA, Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture.
  • Dagit, R.; Downer, A. (1996). Status of transplanted coast live oaks in Southern California. Symposium on Oak Woodlands: Ecology, Management and Urban Interface Issues (Proceedings), San Luis Obispo, CA, Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture.
  • Cudney, D.; Downer, A., et al. (1995). "A non-disruptive technique for kikuyugrass control in cool season turf." California Agriculture 48: 24-28.
  • McGiffen Jr., M.; Greene, R., et al. (1995). "Field tests of methanol as a crop yield enhancer." HortScience 30: 1225-1228.
  • Faber, B.; Downer, A., et al. (1993). "Inexpensive, hand-held moisture meters." HortTechnology 3: 195-196.
  • Cudney, D.; Downer, A., et al. (1993). "Kikuyugrass (Pennisetum clandestinum) management in turf." Weed Technology 7: 180-184.
  • Bellows, T.; Paine, T., et al. (1992). "Biological control of ash whitefly: a success in progress." California Agriculture 46: 27-28.
  • Downer, A.; Koehler, C., et al. (1991). "Biology and management of the eugenia psyllid (Trioza eugeniae Froggatt)." Journal of Environmental Horticulture 9(3): 137-141.
  • Downer, A.; Cudney, W. (1989). "Glyphosate doesn't harm tall fescue." California Agriculture 43: 13-14.
  • Armentrout, V.; Downer, A., et al. (1987). "Factors affecting infection cushion development by Rhizoctonia solani on cotton." Phytopathology 77: 623-630.
  • Armentrout, V.; Downer, A. (1987). "Infection cushion development by Rhizoctonia solani on cotton." Phytopathology 77: 619-623.
  • Downer, A.; Koehler, C., et al. (1987). "New psyllid pest of California pepper tree." California Agriculture 42: 30-32.
  • Armentrout, V.; Downer, A., et al. (1986). "A simplified branching assay for Rhizoctonia solani." Mycologia 78: 657-663.

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