Vaughn  Walton


Mating disruption
Biological control
Perennial crops
Vaughn Walton
Associate Professor, Extension Entomologist

Extension Horticultural Entomologist and Lead Investigator, Spotted Wing Drosophia

OSU Campus
Department of Horticulture
Oregon Wine Research Institute
4017 Ag and Life Sciences Bldg
Corvallis, OR 97331-7304
United States
(541) 737-3485


  • Mating disruption
  • Modeling
  • Entomopathogenic/Biorational pest control agent
  • Biological control
  • Herbivore-induced plant volatiles
  • Perennial food crops

My work at OSU work focuses to resolve key entomological industry needs in the Pacific Northwest with current focus on Spotted Wing Drosophila, Brown Mamorated Stink Bug, mealybugs and sustainable pest managment in hazelnut orchards.  Previously I studied mites in Oregon vineyards .

The aim of my work is to provide environmentally sustainable and minimal impact pest management strategies for agriculturalists in Oregon and further afield. This is done with knowledge obtained from detailed insect physiological, biological, behavioral, ecological and environmental studies. I have a strong focus to develop monitoring tools and determine economic and action thresholds. This knowledge is then used to apply treatments timed to occur during periods when pests are at their most vulnerable. I have knowledge and experience using alternative pest control methods including various modes of biological control, mating disruption and conventional synthetic pesticides. It is believed that use of a combination of these pest management strategies will minimize environmental impact and optimize sustainable agriculture.

In the past, my work focused on the development of an Integrated Control Program of Vine Mealybug, a cosmopolitan and invasive pest more recently along the grape-growing areas along the west coast of the USA. The invasive characteristics of VMB and pending future colonization into new areas in this region may require focus in my current position at Oregon State University.


Undergraduate: Pests Plagues and Politics


Graduate:        Integrated Pest Management, Whole-Systems Focus

                          Biological Control

                          Special Topics





Ph.D., Entomology, University of Stellenbosch, South Africa, 2003
M.Sc., Integrated Pest Management, University of Stellenbosch, 1998
H.E.D. (Teaching Higher Education Diploma), University of Stellenbosch, 1993
B.Sc., Botany and Zoology, University of Stellenbosch, 1992

Employment History
2012 –Present.  Associate Professor, Department of Horticulture, Oregon State University
2008-2012.  Assistant Professor, Department of Horticulture, Oregon State University, Corvallis, Oregon; Tenure track
2006-2008.  Assistant Professor, Department of Horticulture, Oregon State University, Corvallis, Oregon; Fixed term
2003-2005.  Postdoctoral Researcher, Department of Environmental Science, Policy, and Management, University of California, Berkeley, California
2003–2005.  Research Associate, Department of Conservation Ecology & Entomology, University of Stellenbosch.
1999-2003.  Research and Extension Entomologist, ARC
1997-1998.  Senior Research Technician, ARC
1996.  Research Technician, Agricultural Research Council (ARC)

I accept graduate students for Horticulture


Refereed publications

Wiman, N.G., V.M. Walton, P.W. Shearer, S.I. Rondon, and J.C. Lee. 2014. Factors affecting flight capacity of brown marmorated stink bug, Halyomorpha halys (Hemiptera: Pentatomidae). J. Pest Sci. DOI:10.1007/s10340-014-0582-6.

Tochen, S., D. T. Dalton, N. G. Wiman, C. Hamm, P. W. Shearer, and V. M. Walton. 2014.  Temperature-related development and population parameters for Drosophila suzukii (Diptera: Drosophilidae) on cherry and blueberry. Environ. Entomol.  DOI:

Walton, V. M., 2014.  CABI, Invasive Species Compendium, Brown Marmorated Stink Bug, Impacts:  Original text by V. M., Walton. In: Invasive Species Compendium. Wallingford, UK: CAB International.

Chiu J.C., Jiang X., Zhao L., Hamm C.A., Cridland J.M., Saelao P., Hamby K.A., Lee E.K., Kwok R.S., Zhang G., Zalom F.G., Walton V.M., Begun D.J. 2013. Genome of Drosophila suzukii, the Spotted Wing Drosophila.  G3 (Bethesda). 9;3(12):2257-71. doi: 10.1534/g3.113.008185.

Lee, J. C., Shearer, P. W., Barrantes, L., Beers, E., Burrack, H., Dalton D. T., Dreves, A. J., Gut L. J., Hamby, K A., Havilland D R., Isaacs, R., Nielsen A. L., Richardson, T, Rodriguez-Saona C., Stanley, C. A., Walsh, D. B., Walton V. M., Yee, W. L., Zalom, F. G., and D J. Bruck, 2013. Trap Designs for Monitoring Drosophila suzukii(Diptera: Drosophilidae).   Environ. Entomol. 42(6): DOI:

Rossi Stacconi M.V., Grassi A., Dalton D., Miller B., Ouantar M., Ioriatti C., Walton V., Anfora G. 2013. First field records of Pachycrepoideus vindemmiae (Rondani) (Hymenoptera Pteromalidae) as a parasitoid of Drosophila suzukii in European and Oregon Small fruit production areas.  Entomologia 2013 1; 11-16

Walton V.M., Dalton D.T., Daane K. M., Kaiser C. and Hilton R. J.   2013. Seasonal Phenology of Pseudococcus maritimus (Hemiptera: Pseudococcidae) and Pheromone-Baited Trap Survey of Four Important Mealybug Species in Three Wine Grape Growing Regions of Oregon. Ann Entomol Soc Amer 106(4): 471-478.

Gadino A. N., Walton V. M.  and J. C. Lee, 2012.  Evaluation of methyl salicylate lures on populations of Typhlodromus pyri (Acari: Phytoseiidae) and other natural enemies in western Oregon vineyards.  Biological Control, 2012, 63, 1, pp 48-55.

Lee J. C., Burrack H. J., Barrantes L. D., Beers E. H., Dreves A. J., Hamby K., Haviland D. R., Isaacs R., Richardson T., Shearer P., Stanley C.A., Walsh D. B, Walton V. M. and F. G. Zalom 2012.  Evaluation of monitoring traps for Drosophila suzukii (Diptera: Drosophilidae) in North America. J. Econ Entomol. 2012, 105, 4, pp 1350-1357.

Miller B., Bruck D. J., Walton, V. M., 2012.  Relationship of Black Vine Weevil Egg Density and Damage to Two Cranberry Cultivars.  HortSci 47(5): 1–7.

Gadino A. N, Walton V. M., 2012.   Temperature-related development and population parameters for Typhlodromus pyri (Acari: Phytoseiidae) found in Oregon vineyards.  Exp Appl Acarol 2012, 58, 1, pp 1-10.

Chambers U., Walton V.M. and S. A. Mehlenbacher  2011.  Susceptibility of Hazelnut Cultivars to Filbertworm, Cydia latiferreana. HortSci 46: 1377-1380.

Role: Co-Authored paper; co-author edited earlier and final drafts.

Gadino A. N., Walton V. M. and J. Lee. 2011.  Olfactory response of the predatory mite Typhlodromus pyri (Acari: Phytoseiidae) to methyl salicylate in laboratory bioassays. J Appl Entomol DOI 10.1111/j.1439-0418.2011.01670.x

Daane K. M., Middleton, M. C., Sforza, R., Cooper, M. L., Walton, V. M., Walsh, D. B., Zaveio, T., and R.P.P. Almeida. 2011.  Development of a multiplex to distinguish mealybug species found in North American vineyards. Environ Entomol. DOI:

Dalton D.T., Walton V.M., Shearer, P.W., Walsh, D.B., Caprile J. and R. Isaacs. 2011. Laboratory survival of Drosophila suzukii under simulated winter conditions of the Pacific Northwest and seasonal field trapping in five primary regions of small and stone fruit production in the United States. Pest Manag Sci 67(11): 1368-1374.

Gadino A. N., Walton V. M. and A.J. Dreves. 2011.  Laboratory bioassays to determine impact of six pesticides on the beneficial arthropod, Typhlodromus pyri (Scheuten) (Acari: Phytoseiidae).  Econom Entomol 104(3): 970-977.

Walsh D.B., M.P. Bolda, R. E. Goodhue, A. J. Dreves, J. Lee, D. J. Bruck, V. M. Walton, S. D. O’Neal and F. G. Zalom. 2011.  Drosophila suzukii (Diptera: Drosophilidae): Invasive Pest of Ripening Soft Fruit Expanding Its Geographic Range and Damage Potential. J Integ Pest Mngmt 2(1): 1-7.

Walton V. M., Dreves A. J., Coop L., Jones G. and Skinkis P. 2010.  Degree-Day model for Calepitrimerus vitis (Nalepa 1905) (Acari:  Eriophyidae) and susceptibility feeding damage in Wine Producing areas of Western Oregon. Environ Entomol 39(6): 2006-2016.

Chambers U., Bruck D., Olsen, J., and V. M. Walton. 2010.  Behavior of Over-wintering Filbertworm (Cydia latiferreana) (Lepidoptera: Tortricidae) Larvae and Their Control with Steinernema carpocapsae.  Econom Entomol 103(2): 416-422.

Walton V.M., Kr├╝ger K., Saccaggi D.L., Millar I.M. 2009.  A survey of scale insects (Sternorryncha: Coccoidea) occurring on table grapes in South Africa.  J Insect Sci 9: 47.

Wang X. G., Nadel, H., Johnson, M. W., Daane, K. M., Hoelmer, K., Walton, V. M., Pickett, C. H., and Sime, K. R. 2009.  Crop domestication relaxes both top-down and bottom-up effects on a specialist herbivore.  Basic Appl Ecol 10(3):  216-227.

Gent D.H., D.G. James, L.C. Wright, J.D. Barbour, A.J. Dreves, G.C. Fisher, and V.M. Walton 2009. Effects of powdery mildew fungicide programs on twospotted spider mite (Acari: Tetranychidae), hop aphid (Homoptera: Aphididae), and their natural enemies in hop yards. J Econ Entomol 102(1): 274-286.

Daane K.M., Sime K. R., Wang, X., Nadel, H., Johnson M.W., Walton, V.M., Kirk A. and C.H. Pickett. 2008.  Psyttalia lounsburyi (Hymenoptera: Braconidae), promising biological control agent for the olive fruit fly in California. Biol Contr 44:79-89.

Gutierrez A. P., Daane, K. M., Ponti, L., Walton, V. M. and C. K. Ellis. 2008. Prospective evaluation of the biological control of vine mealybug: refuge effects and climate. J Appl Ecol 45: 524-536.

Walton V. M., A. J. Dreves, D. H. Gent, D. G., James, R. R. Martin, U. Chambers* and P. A. Skinkis. 2007.  Relationship between rust mites, Calepitrimerus vitis (Acari:  Eriophyidae), bud mites Colomerus vitis (Acari: Eriophyidae) and short shoot syndrome in Oregon vineyards.  Int J Acarol 33(4): 307-318.

Bruck D. J., and V.M. Walton. 2007.  Susceptibility of the Filbertworm (Cydia latiferreana, Lepidoptera: Tortricidae) and Filbert Weevil (Curculio occidentalis, Coleoptera: Curculionidae) to Entomopathogenic Nematodes.  J Invert Path 96: 93-96.

Walton V. M., Daane, K. M., Bentley, W. J., Millar, J. G., Larsen, T. E., and R. Malakar-Kuenin. 2006.  Pheromone-based Mating Disruption of Planococcus ficus (Hemiptera: Pseudococcidae) in California Vineyards. J Econ Entomol 99(4): 1280-1290.

Walton V.M. and K.L. Pringle. 2005.  Developmental biology of vine mealybug, Planococcus ficus (Signoret) (Homoptera: Pseudococcidae), and its parasitoid Coccidoxenoides perminutus (Timberlake) (Hymenoptera: Encyrtidae).  African Entomol 13(1):143-147.

Walton V.M., Daane, K.M. and K.L. Pringle. 2004.  Monitoring Planococcus ficus in South African vineyards with sex pheromone-baited traps.  Crop Protect 23: 1089-1096.

Walton V.M. and K.L. Pringle. 2004.  Vine Mealybug, Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), a key pest in South African vineyards: A Review.  S Afr J Enol Vitic 25(2): 54-62.

Daane K.M., Malakar-Kuenen, R., and V.M. Walton. 2004.  Temperature-dependent development of Anagyrus pseudococci (Hymenoptera: Encyrtidae) as a parasitoid of the vine mealybug, Planococcus ficus (Homoptera: Pseudococcidae).  Biol Control 31: 123-132.

Walton V.M. and K. L. Pringle. 2004.  A Survey of Mealybugs and Associated Natural enemies in Vineyards in the Western Cape Province, South Africa. S Afr J Enol Vitic 25(1): 23-25.

Walton, V.M., 2003. Development of an integrated pest management system for vine mealybug, Planococcus ficus (Signoret), in vineyards in the western Cape Province, South Africa. Thesis PhD. University of Stellenbosch, South Africa.

Walton V.M. and K.L. Pringle 2001. The effects of pesticides and fungicides used on Grapevines on the mealybug predatory beetle Nephus boschianus (Coccinellidae, Scymnini).  S Afr J Enol Vitic, 22, 2.; 107-110.

Walton V.M. and K.L. Pringle 1999. Effects of pesticides used on table grapes on the mealybug parasitoid, Coccidoxenoides peregrinus (Timberlake) (Hymenoptera: Encyrtidae). S Afr J Enol Vitic 20, 31 – 34.

Walton V.M. 1998. Evaluation of the effects of pesticides, used on table grapes, on the mealybug parasite, Coccidoxenoides peregrinus (Timberlake) (Hymenoptera : Encyrtidae).  M.Sc. Entomology, University of Stellenbosch.

Book Chapters

Walton V.M., Daane, K.M. and P. Addison. 2011.  Principles of Biological Control in Vineyards.  In: Vineyard Pest Management, Bostanian and Isaacs (Eds.) Elsevier press.

Daane K.M., Walton, V.M., Sforza, R., and R. Ripa. 2011. Mealybugs. In: Vineyard Pest Management, Bostanian and Isaacs (Eds.) Elsevier press.

Peer Reviewed Publications

Pscheidt J. W., Peachey E. and V. Walton 2014. Walnut 2014 Pest Management Guide for the Willamette Valley. Oregon State University Extension Service, EM 8421.

Pscheidt J. W., Peachey E. and V. Walton 2014.  Hazelnut 2014 Pest Management Guide for the Willamette Valley. Oregon State University Extension Service, EM 8328. 

Olsen J., J. W. Pscheidt and V. Walton 2013.  Growing hazelnuts in the Pacific Northwest, Integrated Pest Management.  Oregon State University Extension Service, EM9081.

Hedstrom C., Wiman N., Walton V., Shearer P., Rondon S. and J., Lee 2013.  Brown Marmorated Stink bug, Halyomorpha halys, Oregon state University Extension Service, EM9054. (Also available in Spanish EM 9054 S)

Grafton-Cardwell E., Carroll D., Bentley W., J., Haviland D. R., and V. M. Walton 2013.  Pomegranate:  UCIPM Pest Management Guidelines Publication 3474.

Walton V. and Dalton, D., 2013.  Mealybugs In Section 3, Insect and Mite Management. Field Guide for Integrated Pest Management in Pacific Northwest Vineyards, A PNW Extension Publication, PNW644. (M. Moyer, S O’Neal Eds).

Walton V.M. Lee, J. Bruck D. and A. J. Dreves.  2010. Recognizing Fruit Damaged by Spotted Wing Drosophila (SWD), Drosophila suzukii. EM 9021

Dreves A.J. and V.M. Walton. 2010. Trapping and identifying mealybugs in Oregon vineyards. EM 8998.

Skinkis P., Pscheidt J., Walton V.M., Dreves A.J. , Peachey E., Allen N.,  and J. Sanchez. 2007-2014. Pest Management Guide for Wine Grapes in Oregon. OSU Extension Service EM8413E. (updated annually)

James D., Skinkis, P., and V. M. Walton. 2007-2014. “Grape Pests” In: Pacific Northwest Insect Pest Management Handbook. Pacific Northwest Extension Publication. (updated annually)

Dreves A.J. Walton V.M.,  and G. Fisher. 2009.  Spotted Wing Drosophila: Drosophila suzukii (Matsumura).  A new pest attacking healthy ripening fruit in Oregon.  EM 8911.

Skinkis P., Walton V. M.,  and C. Kaiser. 2009.  Phylloxera: Strategies for Management in Oregon’s Vineyards EC 1463-E.

Walton V. M., Chambers, U, and J. Olsen. 2009.  Hazelnut Pest and Beneficial Insects: An Identification Guide EM 8979-E.

Walton V.M., P. Skinkis, A.J. Dreves, and C. Kaiser. 2009. Grapevine Growth Distortions: A guide to identifying symptoms. Oregon State University Extension Bulletin EM 8975-E.

Skinkis P., A.J. Dreves, V.M. Walton,  and R.R. Martin. 2009. Monitoring for Grapevine Leafroll Virus and Mealybug in Pacific Northwest Vineyards. OSU Extension Bulletin EM 8985.

Walton V.M., Dreves A. J. , Skinkis P., Kaiser C., Buchanan M., Hilton R., Martin R.R., Castagnoli S.,  and S. Renquist 2009. Prevention and Management of Grapevine Leafroll Virus and Mealybugs in Oregon Vineyards. OSU Extension Bulletin EM 8990.

Kaiser C., Pscheidt, J.W., Walton, V. M., and P. Skinkis. 2008.  How to Reduce the Risk of Pesticide Resistance in Winegrape Pests in Oregon.  EM 8968. 

Daane K.M., Cooper, M.L. Triapytsyn S.V., Walton, V.M., Yokota G.Y., Haviland, D.R., Bentley, W.J., Godfrey, K.E. and L.R. Wunderlich. 2008.  Vineyard managers and researchers seek sustainable solutions for mealybugs, a changing pest complex.  California Agriculture. October –December 2008, 167-176.

Walton V.M., Chambers, U., Dreves, A., Bruck, D.J., and J. Olsen. 2007.  Identification of Invasive and Reemerging Pests on Hazelnuts. Extension publication EM 8946-E.

Walton V.M., Dreves, A.J., and P. Skinkis. 2007.  Short Shoot Syndrome of Grapes in the Pacific Northwest.  Extension publication EM 8944-E. 

Daane K. M., Walton, V. M., Bentley W.J., Millar, J., G., Cooper, M.L., Biscay P. J. and G. Y. Yokota. 2006.  Developing a Pheromone Based Mating Disruption Program for the Vine Mealybug. UC Plant Protection Quarterly, Vol. 16, No.1.

Daane K. M., Bentley, W. J., Walton, V. M., Malakar-Kuenin, R., Millar, J. G., Weber, E. A., and C. Gispert. 2006. New controls investigated for vine mealybug. California Agriculture 60(1): 31-38.

Awards and Honors

Oldfield/Jackman Team Award, College of Agricultural Sciences, Oregon State University 2013.

Entomological Society of America Pacific Branch Entomology Team Award, 2012.

Entomological Society of America Pacific Branch Entomology Excellence in IPM Award, 2012.

Savery Award for Outstanding Young Faculty, College of Agricultural Sciences, Oregon State University, 2008.

South African Deciduous Fruit Producers Trust travel award, for Outstanding Scientists, 2003.

South African Society of Enology and Viticulture Scientist Award for most outstanding scientific contribution published in our journal or the most outstanding innovation in our industry, 1999.