Barbara Shew

Research Assistant Professor and Extension Specialist



  • Emma Lookabaugh, Ph.D. Dissertation topic:  Production factors that influence the interaction between Pythium aphanidermatum and poinsettia in commercial greenhouse systems
  • Michael Cannon, M.S. Thesis topic: Yield loss due to Sclerotinia blight of peanut
  • Amy Taylor, Master of Plant Pathology
  • Chutsuda Junsopa, visiting scholar from Khon Kaen University, Thailand
  • Emma Lookabaugh, M.S. 2013. Thesis title: Understanding the impact of Pythium species on floricultural crops in North Carolina
  • Sarah Rurak, M.S. 2009. Thesis title: Evaluation of Biological and Other Novel Seed and Soil Treatments for Organic Peanut Production. Current position: Ph.D. student, Cornell University
  • Damon Smith, Ph.D. 2007, M.S., 2004. Thesis title: Biology and Epidemiology of Sclerotinia minor on Peanut (Arachis hypogaea L.). Current position: Assistant Professor, University of Wisconsin
  • Laura Duffie, M.S. 2003. Effects of intercropping corn and peanut on peanut leaf spot management and the spatial and temporal epidemiology of Cercospora arachidicola. Current position: USDA-APHIS


1976 B.S. Plant Pathology, Colorado State University
1980 M.S. Plant Pathology, North Carolina State University
1983 Ph.D. Plant Pathology, North Carolina State University


Pythium in Floricultural Crops (Emma Lookabaugh)

North Carolina is a major producer of floricultural crops and Pythium is frequently diagnosed on floricultural samples submitted to the Plant Disease and Insect Clinic (PDIC). Greenhouses in North Carolina previously had not been systematically sampled for the presence of Pythium. The severity of the problem, the Pythium species involved, and the extent of mefenoxam resistance in greenhouse populations were unknown. To address these questions, graduate student Emma Lookabaugh collected herbaceous ornamentals exhibiting symptoms of Pythium root rot from 18 greenhouses in 14 counties in North Carolina. Isolates were identified to species by sequencing of the ITS rDNA region. More than half of the 277 isolates collected were resistant to mefenoxam. Resistant and sensitive strains were found within the same greenhouse and species. We plan to use the results of this research to provide mefanoxam resistance screening services to growers through the Plant Disease and Insect Clinic.

Peanut diseases

Peanuts are grown on about 90,000 acres in North Carolina. The crop is affected by several serious diseases, including leaf spots, southern stem rot, Sclerotinia blight, Cylindrocladium black rot, and Spotted wilt. My research aims to develop integrated disease management tactics that take advantage of host resistance and weather-based disease advisories to minimize the use of fungicides and other pesticides in peanut production. Currently, I am focusing on developing reduced input disease control methods that can be used on the new partially resistant cultivars Bailey, Sugg, Sullivan and Wynne. I work with peanut breeder Dr. Tom Isleib in evaluation of disease resistance in new breeding lines. I also work with Dr. David Jordan to understand the impacts of cultural practices on disease development and crop health.

Extension & Outreach

Plant Disease and Insect Clinic

I serve as the Director of the Plant Disease and Insect Clinic at NCSU. The clinic is staffed with two full-time plant disease diagnosticians, Shawn Butler and Mike Munster, and full-time entomologist, Matt Bertone. Graduate student Emma Lookabaugh diagnoses diseases of tomatoes and other crops. The clinic provides diagnostic training for County Agents and Master Gardeners and uses social media (Facebook, Twitter, and Blog) for outreach to a wide audience of Extension personnel, farmers, nurseries, and homeowners.


As part of a team that includes Dr. David Jordan in Crop Science, Dr. Rick Brandenburg in Entomology, and county extension personnel, I have extension responsibilities for peanut diseases. We prepare educational materials, conduct field testing, and participate in grower meetings, demonstrations and field days. In addition, in cooperation with the North Carolina State Climate office, I provide daily peanut disease advisories for peanut growers in North Carolina.

Peanut Information
Agricultural Chemicals Manual
Peanut Risk Management
Peanut Disease Photos
Peanut Disease Advisories -click on this link to view today’s weather based disease advisories and for information on how to interpret advisories. You may contact Dr. Shew to receive daily advisory emails.
Peanut Scouting Manual – IPM Center

Selected Publications

Junsopa, C., Jogloy, S., Saksirirat, W., Songsri, P, Kesmala, T., Pathanothai, A., Shew, B.B. 2016.  Inoculation with Sclerotium rolfsii, cause of stem rot in Jerusalem artichoke, under field conditions. Eur. J. Plant Pathology Doi 10.1007/s/0658-016-089-1

Boudreau, M.A., B. B. Shew, and L.E. Duffie. 2015. Impact of intercropping on epidemics of groundnut leaf spots: defining constraints and opportunities through a 7-year field study. Plant Pathology Doi 10.1111/ppa.12440.

Lookabaugh, E.C., Ivors, K.M., Shew, B.B. 2015. Mefenoxam sensitivity, aggressiveness, and identification of Pythium species causing root rot on floriculture crops in North Carolina. Plant Disease 99:1550-1558.

Isleib, T.G., Milla-Lewis, S.R., Pattee, H.E., Copeland, S.C., Zuleta, M.C., Shew, B.B., Hollowell, Sanders, T.H., Dean, L.O. Hendrix, K.W., Balota, M., Chapin, J.W., and Monfort, W.S. 2015. Registration of ‘Sugg’ Peanut. J. Crop Regist. 9:44-52

Jordan, D.L., P. D. Johnson, T. Corbett, J. Schultheis, B. Shew, R. Brandenburg, W. Ye. 2014. Peanut response to crop rotations including clary sage, snap bean, and sweet potato. Crop Manag. doi:10.2134/CM-2014-0038-RS

Drake, W.L., D. L. Jordan, P. D. Johnson, B. B. Shew, R. L. Brandenburg, T. Corbett. 2014. Peanut response to planting date, tillage, and cultivar in North Carolina. Agronomy Journal 106: 486-490

Isleib, T.G., B.B. Shew, S.R. Milla-Lewis, W.B. Dong, S.C. Copeland, C. Arellano. 2013. Stability analysis of incidence of tomato spotted wilt in virginia-type peanut cultivars and breeding lines. Peanut Sci. 40:24-30.

Chahal, G.S., D.L. Jordan, B.B. Shew, R.L. Brandenburg, J.D. Burton, and D. Danehower. 2012. Interactions of Agrochemicals Applied to Peanut; Part 2: Effects on Fungicides. Crop Protection

Partridge-Telenko, D.E., J. Hu, D. M. Livingstone, B. B. Shew, P. M. Phipps, and E. A. Grabau. 2011. Sclerotinia Blight Resistance in Virginia-Type Peanut Transformed with a Barley Oxalate Oxidase Gene. Phytopathology 101: 786-793.

Ruark, S.J., and Shew, B.B. 2010. Evaluation of microbial, botanical, and organic treatments for control of peanut seedling diseases. Plant Dis. 84:445‐454.

Isleib, T.G., Milla-Lewis, S.R., Pattee, H.E., Copeland, S.C., Zuleta, M.C., Shew, B.B., Hollowell, J.E., Sanders, T.H., Dean, L.O., Hendrix, K.W., Balota, M. 2010. Registration of Bailey Peanut. Journal of Plant Registrations 5:1-13.

Carley, D.S., Jordan, D.L., Shew, B.B., Sutton, T.B., Dharmasri, L.C., and Brandenburg, R.L. 2009.
Influence of Digging Date and Fungicide Program on Canopy Defoliation and Pod Yield of Peanut (Arachis hypogaea L.). Peanut Science 36:77‐84.

Jordan, D. L., Fisher, L. R., Shew, B. B., Marshall, T., Johnson, P. D., Ye, W., and Brandenburg, R. L. 2009. Comparison of cropping systems including corn, peanut, and tobacco in the North Carolina Coastal Plain. Crop Management doi:10.1094/CM‐2009‐0612‐01‐RS.

Smith, D.L., Garrison, M.C., Hollowell, J.E., Isleib, T.G., and Shew, B.B. 2008. Evaluation of application timing and efficacy of the fungicides fluazinam and boscalid for control of Sclerotinia blight of peanut. Crop Protection 27:823‐833.

Hollowell, J.E., Isleib, T.G., Tallury, S.P., Copeland, S.C. and Shew, B.B. 2008. Screening of virginia‐type peanut breeding lines for resistance to Cylindrocladium Black Rot and Sclerotinia Blight in the greenhouse. Peanut Science 35: 18‐24.

Cantonwine, E.G., A. K. Culbreath, B. B. Shew, and M. A. Boudreau. 2008. Efficacy of organically acceptable fungicides for management of early and late leaf spot of peanut. Plant Health Progress doi:10.1094/PHP‐0317‐03‐RS.

Jordan, D.L., B.B. Shew, J.S. Barnes, T. Corbett, J. Alston, P.D. Johnson, W. Ye, and R.L. Brandenburg. 2008. Pest reaction, yield, and economic return of peanut cropping systems in the North Carolina coastal plain. Crop Management doi:10.1094/CM‐2008‐1008‐01‐RS.

Jordan, D.L., J.S. Barnes, T. Corbett, C.R. Bogle, P.D. Johnson, B.B. Shew, S.R. Koenning, W. Ye, and R.L.Brandenburg. 2008. Crop response to rotation and tillage in peanut‐based cropping systems.Agron. J. 100:1580‐1586.

Smith, D.L, J.E. Hollowell, T.G. Isleib, and B. B. Shew. 2007. A site‐specific, weather‐based disease model for Sclerotinia blight of peanut. Plant Dis. 91:1436‐1444.

Isleib, T.G., P.W. Rice, S.C. Copeland, R.W. Mozingo II, J.B. Graber, B. Shew, D.L. Smith, H. Melouk, and H.T. Stalker. 2006. Registration of N96076L peanut germplasm. Crop Sci. 46:2329‐2330.

Smith, D.L., J.E. Hollowell, T.G. Isleib, and B.B. Shew. 2006. Analysis of factors that influence the epidemiology of Sclerotinia minor on peanut. Plant Dis. 90:1425‐1432.

Hollowell, J.E. and B.B. Shew. 2005. First Report of Sclerotinia minor on Allium vineale in North Carolina. Plant Dis. 89:908. Published on‐line as DOI: 10.1094/PD‐89‐0908C.

Hollowell, J.E. and B. B. Shew. 2005. First Report of Sclerotinia minor on Sida spinosa in North Carolina. Plant Dis. 89:1128. Published on‐line as DOI: 10.1094/PD‐89‐1128A.

J.E. Hollowell and B.B. Shew. 2004. First report of Carolina geranium as a host of Sclerotinia minor. Plant Disease 88: 312.

J.E. Hollowell and B.B. Shew. 2004. First report of common chickweed as a host of Sclerotium rolfsii. Plant Disease 88: 426.

Hollowell, J.E., B.B. Shew, M.A. Cubeta, and J.W. Wilcut. 2003. Weed species as hosts of Sclerotinia minor in peanut fields. Plant Disease 87:198‐199.

Hollowell, J.E., B.B. Shew, and T.G. Isleib. 2003. Evaluating isolate aggressiveness and host resistance from peanut leaflet inoculations with Sclerotinia minor. Plant Disease 87:402‐406.

Lemay, A.V., J.E. Bailey, and B.B. Shew. 2002. Resistance of peanut to Sclerotinia blight and the effect of acibenzolar‐S‐methyl and fluazinam on disease incidence. Plant Disease 86: 1315‐1317.

Stalker, H.T., M.K. Beute, B.B. Shew, and K.R. Barker. 2002. Registration of two root‐knot nematoderesistantpeanut germplasm lines. Crop Sci. 42:312‐313.

Stalker, H. T., M. K. Beute, B. B. Shew, and T. G. Isleib. 2002. Registration of five leaf spot‐resistant peanut germplasm lines. Crop Sci. 42:314‐316.

Selected Technical Reports 

Shew, B.B. 2015. Response of peanut diseases in North Carolina to spray programs with labeled fungicides, 2014. Plant Dis. Mgt. Rep. 9

Shew, B.B. 2015. Response of peanut diseases in North Carolina to in-furrow inoculation and fungicide applications, 2014. Plant Dis. Mgt. Rep. 9

Shew, B.B.  2014. Evaluation of Abound, Convoy, and Folicur for stem rot control on stevia in North Carolina, 2014. Plant Dis. Mgt. Rep. 9

Shew, B.B. 2013.  Evaluation of experimental fungicides for peanut disease control in North Carolina, 2013. Plant Dis. Mgt. Rep. 8

Shew, B.B. 2011. Evaluation of Abound plus Alto for control of peanut diseases in North Carolina, 2011. Plant Dis. Mgt. Rep. 6

Shew, B.B. 2011. Evaluation of Fontelis and Topguard for control of peanut diseases in North Carolina, 2011. Plant Dis. Mgt. Rep. 6

Shew, B.B. 2011. Evaluation of spray programs with labeled fungicides for the control of peanut diseases in North Carolina, 2012.     Plant Dis. Mgt. Rep. 6

Shew, B.B., B.B. 2010. Evaluation of Topguard and other fungicides for the control of peanut diseases in North Carolina, 2009. Plant Dis. Mgt. Rep. 4

Shew, B.B., B.B. 2010. Evaluation of in-furrow and foliar fungicides for control of peanut diseases in North Carolina, 2009. Plant Dis. Mgt. Rep. 4