Todd Einhorn

Todd Einhorn

Contact Me

Associate Professor

(517) 353-0430


Joined Department

August 1, 2016


60% Research

25% Extension

15% Teaching


Ph.D. Pomology, 2006, Colorado State University
B.S. Horticultural Science, 2001, Colorado State University

Prior Academic Positions

Associate Professor, Oregon State University (2014-2016)    

Assistant Professor, Oregon State University (2008-2014)

Assistant Professor, Fresno State University (2006-2008)

Honors, Awards, Academic Fellowships

2019    University of Pisa Visiting Fellow, Pisa, Italy, June-July 2019.

2017    Dr. Tim Facteau Outstanding Contributor Award, Columbia Gorge Fruit Growers

2016    Silver Pear Award, Washington State Horticultural Association

2015    Experiment Station Section Excellence in Multistate Research Award:  NC140, Improving Economic and Environmental Sustainability in Tree-Fruit Production Through Changes in Rootstock Use. USDA (Team Award).

2014    Research Fellowship:  DEPI, Tatura Research Center, Victoria, Australia. March 6-21, 2014. Focus: Pear horticulture.

2011    Teaching Fellowship:  International Masters in Horticultural Sciences (IMaHS) program.  University of Bologna, Bologna Italy.  Host Faculty: Dr. Stefano Musacchi. September 26-October 30, 2011

Research (Current Projects)

We are developing innovative horticultural strategies to manage apple, pear and tart cherry production systems. Focus is on understanding plant growth development and environmental stress to optimize tree fruit production.

Orchard Establishment

Ameliorating transplant shock and improving early canopy infill and cropping of apple trees via containerized tree production. Characterization of root and shoot growth and development in field and container systems and their relationship with orchard establishment.

Rootstock Evaluation and Characterization

Novel germplasm sources for pear (Amelanchier and Cydonia) and apple are currently under evaluation for conferring cold hardiness, dwarfing, precocity and productivity to scion selections.

Thinning and Plant Growth Regulation

Focus is on the identification of underlying environmental and physiological mechanisms regulating fruit growth, development, and abscission or retention. Characterization of plant growth regulator action to improve efficacy for fruit thinning and canopy management. Evaluation of netting to manage fruit set.

Tart Cherry Canopy Architecture and Mechanized Harvest

Focus is on developing training systems and modifying canopy architecture via horticultural strategies (root pruning, PGRs, rootstocks, canopy hedging and limb renewal) to facilitate over-the-row harvest systems.

Fruit Growth and Development

We are interested in characterizing pre-bloom development of cherry and identifying objective indicators of dormancy transitions to improve our understanding and capacity to manage freeze resistance/sensitivity. 

Graduate Students and Postdoctoral Research Fellows/Associates


Laura Hillmann, Ph.D. candidate (2019- )

Chayce Griffith, M.S. candidate (2019- )

Tye Wittenbach, M.S. candidate (2018- ). Project: The role of ABA on xylem development, water and calcium delivery, and bittepit disorder of 'Honeycrisp' apple from bloom to maturation.

Andrew Hubbard, Ph.D. candidate (2015- ). OSU. Project: Effect of early defoliation of sweet cherry trees on cold acclimation, dormancy and susceptibility to infection by Pseudomonas sp.

Dr. Mokhles A Elsysy, Postdoctoral Research Associate (2017- ). Dr. Elsysy works on several projects focused on fruit growth and development and tree fruit physiology.


2018    Laura Hillmann, M.S. Co-chair with Dr. Michael Blanke, University of Bonn, Germany. Project: Preanthesis development, growth, and freeze sensitivity of tart cherry pistils.

2015    Matthew Arrington, M.S. OSU. Project: Root pruning and thinning approaches to manage pear cropload.

2012-2016    Dr. David Gibeaut, Postdoctoral Research Associate. Developmental biology and modeling of sweet cherry fruit growth.

International Graduate Students Hosted

2019    Margherita Germani, M.S. candidate, University of Bologna, Italy. April 15- October 1, 2019. Project: Abscission and ethylene production rates of tart cherry flowers and fruitlets treated with ethephon.

2015    Ambroise Sarret, M.S. candidate, AgroSup Dijon, France. April 20, 2015- August 23, 2015.  Project:  The effects of early termination of irrigation water on sweet cherry production and fruit quality.

2014    Ana Paula Lima, Ph.D. candidate, Universidale Federal de Pelotas, Brazil. March 31, 2014- October 15, 2014.  Project:  Effect of plant growth bio-regulators on floral biology, fruit set and production efficiency.

2013    Aritz Kerman Monge Sánchez, M.S. candidate, Universitat Politècnica de València, School of Agricultural Engineering and Environment, Valencia, Spain. July 10, 2013- December 10, 2013.  Project:  Application of root pruning to pear trees.

2012    Mateus Da Silveira Pasa, Ph.D. candidate, Universidale Federal de Pelotas, Brazil. March 15, 2012- February 20, 2013.  Project:  Control of pear vigor with plant bio-regulators.

2011    Lucie Marchand, M.S. candidate, Agrocampus Ouest, Centre d’Angers, National Institute of Horticulture, Angers, France. May-August, 2011.  Project:  Deficit irrigation of sweet cherry.


Hendrickson, C., Hewitt, S., Swanson, M.E., Einhorn, T. and Dhingra, A. 2019. Evidence for pre-climacteric activation of AOX transcription during cold-induced conditioning to ripen in European pear (Pyrus communis L.). PLOS One, In-press.

Elsysy, M., Hubbard, A. and Einhorn, T.C. 2019. Postbloom thinning of 'Bartlett' pear with metamitron. HortScience. In-press.

Elsysy, M. and Einhorn, T.C. 2019. Air root pruning containers alter root architecture and increase canopy and root growth of apple trees compared to field grown liners. Acta Hort. In-press.

Gallardo, K., Grant, K., Brown, D., McFerson, J., Lewis, K., Einhorn, T., and Sazo, M. 2019. Perceptions of precision agriculture technologies in the U.S. fresh apple industry. HortTechnology

Elsysy, M. Serra, S., Schwallier, P., Musacchi, S. and Einhorn, T.C. 2019. Net enclosure of 'Honeycrisp' and 'Gala' apple trees at different bloom stages affects fruit set and alters seed production. Agronomy 9, 478; doi:10.3390/agronomy9090478

Einhorn, T. 2019. Challenges and opportunities in pear cultivation. In: Lang, L (Ed.), Achieving sustainable cultivation of temperate zone tree fruits and berries, Volume 2: Case studies. Burleigh Dodds Science Publishing, Cambridge, UK, pp. 157-216.

Dong, Y., Wang, Y. and Einhorn, T.C. 2018. Characterization of postharvest physiology, storage quality and physiological disorders of ‘Gem’ pear (Pyrus communis) treated with 1-Methylcyclopropene. Scientia Horticulturae 240: 631-637.

Carra, B., Pasa, M.S., da Silva, C.P., do Amaranted C.V.T., Steffensd, C.A., Bartnickid, V.A., Ciottab, M.N., Mello-Fariasa, P.C., and Einhorn, T. 2018. Early spring inhibition of ethylene synthesis increases fruit set and yield of ‘Rocha’ pear trees in Southern Brazil. Scientia Horticulturae 232: 92-96.

Einhorn, T.C., M. Arrington. 2018. ABA and shade inhibit photosynthesis and increase abscission of ‘Bartlett’ pears but are not additive. Journal of Plant Growth Regulation 37: 300-308.

Arrington, M., Pasa, M.S., Einhorn, T.C. 2017. Postbloom thinning response of ‘Bartlett’ pears to abscisic acid. HortScience 52(12): 1765-1771.

Pasa, M.S. and Einhorn, T. 2017. Prohexadione calcium (effects) on shoot growth of ‘Starkrimson’ pear trees. Brazilian Journal of Horticultural Science 52 (2): 75-83.

Gibeaut, D., Whiting, M.D., and Einhorn, T. 2017. Time indices of multiphasic development in genotypes of sweet cherry are similar from dormancy to cessation of pit growth. Annals of Botany 119: 465-475.

Wang, Y. and Einhorn, T.C. 2017. Harvest maturity and crop load influence pitting susceptibility and postharvest quality deterioration of sweet cherry (Prunus avium L.). Acta Hort. 1161: 613-620. 

Wang, Y. and Einhorn, T.C. 2017. Optimizing preharvest application rate of gibberellic acid (GA3) and homobrassinolide (HBR) to improve shipping quality of sweet cherry (Prunus avium L.). Acta Hort. 1161: 411-416. 

Einhorn, T. and Wang, Y. 2016. Characterizing the effect of harvest maturity on ripening capacity, postharvest fruit quality, and storage life of ‘Gem’ pear. Journal of the American Pomological Society 70 (1): 26-35.

Xie, X., Einhorn, T., and Wang, Y. 2015. Inhibition of Ethylene Biosynthesis and Associated Gene Expression by Aminoethoxyvinylglycine and 1-Methylcyclopropene and Their Consequences on Eating Quality and Internal Browning of ‘Starkrimson’ Pears.  Journal of the American Society for Horticultural Science 140 (6): 587-596. 

Autio, W., J. Cline, T. Einhorn, G. Lang, R. Marini, G. Reighard, and T. Robinson. 2015. 2014 Progress Report – Brief summaries of NC-140 rootstock trials. Compact Fruit Tree 48 (2): 6-8.

Castagnoli, S., Long, L., Shearer, P., Pscheidt, Peachey, E., and Einhorn, T. 2015. Pest Management Guide for Tree Fruits in the Mid-Columbia Area. Oregon State University Extension Bulletin EM 8203. Corvallis, OR.

Pasa, M., and Einhorn, T. 2014. Heading cuts and prohexadione-calcium affect the growth and development of ‘d’Anjou’ pear shoots in a high-density orchard. Scientia Horticulturae 168: 267-271. 

Bell, R., van der Zwet, T., Castagnoli, S., Einhorn, T., Turner, J., Spotts, R., Moulton, G.A., Reighard, G.L. and Shane, W.W. 2014. ‘Gem’ Pear. HortScience 49 (3): 361-363.

Einhorn, T., Pasa, M., and Turner, J.  2014. ‘D’Anjou’ pear shoot growth and return bloom are reduced by prohexadione-ca. HortScience 49(2): 180-187.

Li, P., Zhang, Y., Einhorn, T., and Cheng, L. 2014. Comparison of phenolic metabolism and primary metabolism between green ‘Anjou’ pear and its bud mutation, red ‘Anjou’.  Physiologia Plantarum 150: 339-354.

Einhorn, T., Wang, Y. and Turner, J.  2013. Pre-harvest applications of Gibberellic Acid (GA3) improve fruit firmness and postharvest fruit quality of late-season sweet cherry cultivars. HortScience 48 (8): 1010-1017. 

Einhorn, T., Castagnoli, S., Smith, T., Turner, J., and Mielke, E.  2013. Summary of the 2002 Pacific Northwest Pear Rootstock Trials:  Performance of ‘d’Anjou’ and ‘Golden Russet Bosc’ pear on eight Pyrus rootstocks. Journal of the American Pomological Society 67 (2):  80-88.

Einhorn, T., Pasa, M., and Turner, J. 2013. Promotion and management of pear fruiting. Good Fruit Grower 64 (6): 42-43.

Einhorn, T., Pasa, M., and Musacchi, S. 2013. Vigor control and promotion of fruiting of pear trees. Good Fruit Grower 64 (4):  35-37.

Einhorn, T., Turner, J., and Laraway, D.  2012.  Effect of reflective fabric on yield of mature ‘d’Anjou’ pear trees.  HortScience 47 (11):  1580-1585.

Einhorn, T., Caspari, H.W., and Green, S.  2012.  Total soil water content accounts for augmented ABA leaf content and stomatal regulation of split-rooted apple trees during alternate soil drying.  Journal of Experimental Botany 63 (14):  5365-5376.

Elkins, R., Bell, R., and Einhorn, T. 2012. Needs Assessment for Future US Pear Rootstock Research Directions Based on the Current State of Pear Production and Rootstock Research. Journal of the American Pomological Society 66 (3):  153-163.

Sugar, D. and Einhorn, T.C.  2012. Induction of pear ripening capacity as influenced by harvest maturity, conditioning temperature, and ethylene treatment. Acta Hort. 945: 303-308.

Einhorn, T., Castagnoli, S., Turner, J., and Bell, R. 2012. A gem of a pear. Good Fruit Grower 63 (14): 25-26.

Einhorn, T. 2012. Irrigation strategies for Sweet Cherry Production. Good Fruit Grower 63 (7): 32-35.

Einhorn, T., Laraway, D., and Turner, J. 2011. Cropload management does not consistently improve crop value of ‘Sweetheart’/’Mazzard’ sweet cherry trees. HortTechnology 21 (5): 546-553. 

Sugar, D. and Einhorn, T.  2011. Harvest maturity and conditioning temperature influences induction of ripening capacity in ‘d’Anjou’ pear fruit.  Postharvest Biology and Technology 60: 121-124.

Einhorn, T., Turner, J., and Laraway, D.  2011. Reflective fabric improves intra-canopy light levels and increases yield in a low-density, mature ‘d’Anjou’ pear orchard. Acta Hort. 909:  565-570. 

Einhorn, T., Postman, J., and Turner, J.  2011. Characterization of cold hardiness in quince:  Potential pear rootstock candidates for Northern pear production regions. Acta Hort. 909: 137-144.    

Sugar, D. and Einhorn, T.  2011.  Harvest maturity, conditioning temperature, and ethylene treatment influence induction of ripening capacity in ‘d’Anjou’ pear fruit. Acta Hort. 909: 719-724.    

Castagnoli, S., Turner, J., Einhorn, T., and Bell, R.  2011.  Performance of US 71655-014, a fire blight resistant pear selection from the USA. Acta Hort. 909: 177-182.    

Lang, G.A., Robinson, T., Einhorn, T., Embree, C., Grant, J., Ingels, C., Neilsen, D., Neilsen, G., Pokharel, R., Hirst, P., Kushad, M., and Parra-Quezada, R. 2011. Establishment of 12 regional pedestrian cherry orchard systems trials- 2010 progress report. Compact Fruit Tree 44 (3):  5-6.

Einhorn, T., Turner, J., and Postman, J. 2011. Cold hardy quince. Good Fruit Grower 62 (14): 23-24.

Crisosto, C., Bremer, V., Ferguson, L., Norton, M., and Einhorn, T. 2010. Preharvest ethephon eliminates first crop figs. HortTechnology 20 (1): 173-178.

Einhorn, T., Turner, J., and Laraway, D. 2010.  Reflective fabric increases yield in low density ‘d’Anjou’ pears. Good Fruit Grower 61 (14): 13-15.

Einhorn, T., Caspari, H.W., and Green, S.  2009.  Estimation of containerized single stem and split-rooted, non-fruiting apple tree water use using miniaturized heat pulse probes. Acta Hort. 846: 285-292.