Thomas Forge, Ph.D.

Research Scientist

Applied Soil Ecology / Nematology

Current research and/or projects

General area of research is applied soil ecology, with an emphasis on: (1) Ecology and management of plant-parasitic nematodes; and (2) Integrated root health management for perennial horticulture crops.

Current projects:

  • Impacts of plant-parasitic nematodes on perennial fruit production in British Columbia
  • Comparative tolerance and resistance of new cherry and apple rootstocks to plant-parasitic nematodes
  • Identification and distribution of plant-parasitic nematode species of concern to agriculture in western Canada
  • Pre-plant soil and water management practices to suppress plant-parasitic nematodes and improve replant establishment of perennial fruit crops
  • Interactive influences of organic amendments, mulches and alternative irrigation practices on nematode population dynamics in orchards and vineyards

Education and awards

  • Ph.D. (Plant Pathology), University of Wisconsin-Madison
  • B.Sc. (Biology), Kansas State University

Key publications

For a complete list of Publications: Thomas Forge on AAFC Online


  • Watson, T.W., T.A. Forge, L.M. Nelson. 2018. Pseudomonads contribute to regulation of Pratylenchus penetrans (Nematoda) populations on apple. Canadian Journal of Microbiology 64: 1-11.
  • Watson, T.W., L.M. Nelson, D. Neilsen, G.H. Neilsen, T.A. Forge. 2018. Low-volume irrigation systems influence Pratylenchus penetrans populations, root colonization by arbuscular mycorrhizal fungi, and replant establishment of sweet cherry. Scientia Horticulturae 239: 50-56.


  • Watson, T.W., L.M. Nelson, D. Neilsen, G.H. Neilsen, T.A. Forge. 2017. Soil amendments influence Pratylenchus penetrans populations, beneficial rhizosphere microorganisms, and growth of newly planted sweet cherry. Appl. Soil Ecol. 117–118: 212–220.
  • Neilsen, D., G.H. Neilsen, T. Forge and G. A. Lang. 2017. Dwarfing rootstocks and training systems affect initial growth, cropping and nutrition in ‘Skeena’ sweet cherry. Acta Hortic. 1130: 199-205.
  • Zasada, I., Peetz, A., Forge, T. 2017. Pratylenchus species associated with blueberry (Vaccinium spp.) and weed species in the Pacific North-west of North America. Canadian Journal of Plant Pathology. DOI:
  • Mathew, M.D., N.D. Mathew, A. Miller, M. Simpson, V. Au, S. Garland, M. Gestin, M.L. Edgley, S. Flibotte, A. Balgi, J. Chiang, G. Giaever, P. Dean, A. Tung, M. Roberge, C. Roskelley, T. Forge, C. Nislow, D. Moerman.2017. Using C. elegans forward and reverse genetics to identify new compounds with anthelmintic activity. PLoS Negl Trop Dis 10(10): e0005058. doi:10.1371/journal.pntd.0005058
  • Neilsen, G.H., D. Neilsen and T. Forge. 2017. Advances in soil and nutrient management in apple cultivation. In: Achieving Sustainable Production of Apples, K. Evans (Ed.). Burleigh Dodds Science Publishing Limited, Cambridge.
  • Neilsen, G., D. Neilsen, T. Forge. 2017. Environmental Limiting Factors for Cherry Production. Chapter 9 In: Cherries: Botany, Production and Uses. Edited by J Q Garcia, INRA Bordeaux, France, A Iezzoni, Michigan State University, USA, J Pulawska, Research Institute of Horticulture, Poland, G Lang, Michigan State University, USA. 550 pages.


  • Hannam, K.D., Neilsen, G.H., Forge, T.A., Neilsen, D., Losso, I., Jones, M.D., Nichol, C., Fentabil, M.M. 2016. Irrigation practices, nutrient applications and mulches affect soil nutrient dynamics in a young Merlot (Vitis vinifera L.) vineyard. Canadian Journal of Soil Science 96: 23–36.
  • Fentabil, M.M., Nichol, C.F., Neilsen, G.H., Hannam, K.D., Neilsen, D., Forge, T.A., Jones, M.D. 2016. Effect of micro-irrigation type, N-source and mulching on nitrous oxide emissions in a semi-arid climate: An assessment across two years in a Merlot grape vineyard. Agricultural Water Management 171, 49–62.
  • Forge, T., Kenney, E., Hashimoto, N., Neilsen, D., Zebarth, B. 2016. Compost and poultry manure as preplant soil amendments for perennial fruit crops: Comparative effects on root lesion nematodes, soil quality and risk of nitrate leaching. Agriculture, Ecosystems and Environment 223, 48-58.
  • Forge, T.A., Neilsen, G.H., and Neilsen, D. (2016). "Organically acceptable practices to improve replant success of temperate tree-fruit crops. Scientia Horticulturae.", Scientia Horticulturae, 200, pp. 205-241. doi : 10.1016/j.scienta.2016.01.002.
  • Hannam, K.D., Kehila, D., Millard, P., Midwood, A., Neilsen, D., Neilsen, G.H., Forge, T.A., Nichol, C., and Jones, M.D. (2016). "Bicarbonates in irrigation water contribute to carbonate formation and CO2 production in orchard soils under drip irrigation.", Geoderma, 266, pp. 120-126. doi : 10.1016/j.geoderma.2015.12.015.
  • Neilsen, D., Neilsen, G.H., Guak, S., and Forge, T.A. (2016). "Consequences of deficit irrigation and crop load reduction on plant water relations, yield and quality of 'Ambrosia' apple.", HortScience, 51, pp. 98-106.


  • Forge, T.A., Neilsen, D., Neilsen, G., Watson, T. 2015. Using compost amendments to enhance soil health and replant establishment of tree-fruit crops. Acta Horticulturae 1146: 103-108.
  • Zebarth, B., Forge, T., Goyer, C., Brin, L. 2015. Effect of soil acidification on nitrification in soil. Canadian Journal of Soil Science 95: 359-363. DOI: 10.4141/CJSS-2015-040.
  • Forge, T.A., Larney, F.J., Kawchuk, L.K., Pearson, D.C., Koch, C., Blackshaw, R.E. 2015. Crop rotation effects on Pratylenchus neglectus populations in the root zone of irrigated potatoes in southern Alberta. Canadian Journal of Plant Pathology 37: 363-368. DOI: 10.1080/07060661.2015.1066864.
  • Ehret, D.L., Frey, B., Forge, T., Helmer, T., Bryla, D.R. 2015. Age-related changes in response of highbush blueberry plants to drip irrigation. HortScience 50: 486-490.
  • Forge, T., Hashimoto, N., Neilsen, D., Kenney, E., Zebarth, B. 2015. The use of compost as a preplant amendment to minimize impacts of parasitic nematodes and improve soil health and early establishment of red raspberry. Acta Horticulturae 1076: 225-231.
  • Forge, T., Neilsen, G., Neilsen, D., O’Gorman, D., Hogue, E. 2015. Organic orchard soil management practices affect soil biology and organic matter. Acta Horticulturae 1076: 77-83.
  • Zebarth, B.J., Ryan, C., Graham, G., Forge, T.A., Neilsen, D. 2015. Groundwater monitoring to support development of BMPs for groundwater protection: The Abbotsford-Sumas aquifer case study. Groundwater Monitoring and Remediation 35: 82-96.


  • Forge, T.A., Walters, T.W., Koch, C. 2014. Use of composted dairy manure solids mulch for raspberry:  Influences on soil nematode communities and N and P availability. Compost Science and Utilization 22: 230-241. DOI 10.1080/1065657X.2014.930677.
  • Ehret, D. L., Frey, B., Forge, T., Helmer, T., Bryla, D. R. and Zebarth, B. J. 2014. Effects of nitrogen rate and application method on early production and fruit quality in highbush blueberry. Can. J. Plant Sci. 94: 1165-1179.
  • Neilsen, G. H., D. Neilsen, F. Kappel, and T. Forge. 2014. Interaction of irrigation and soil management on sweet cherry productivity and fruit qualityat different crop loads that simulate those occurring by environmental extremes. HortScience 49: 215-220.
  • Neilsen, G., Forge, T., Angers, D., Neilsen, D., Hogue, E. 2014. Suitable orchard floor management strategies in organic apple orchards that augment soil organic matter and maintain tree performance. Plant Soil. DOI 10.1007/s11104-014-2034-8.


  • Neilsen, G., T. Forge, D. Neilsen, D. O’Gorman, E. Hogue, D. Angers, and N. Bissonnette. 2013. Soil management in organic production systems. Acta Hortic. 1001:295-302.
  • Forge, T., Koch, C., Temple, W., and Bomke, A. 2013. Using compost as mulch for highbush blueberry. Acta Horticulturae 1001: 369-376.
  • Forge, T.A., Neilsen, G.H., Neilsen, D., Hogue, E.J., and Faubion, D. 2013. Composted Dairy Manure and Alfalfa Hay Mulch Affect Soil Ecology and Early Production of ‘Braeburn’ Apple on M.9 Rootstock. HortScience, 48(5): 645-651.
  • Hannam, K.D., Neilsen, G.H., Forge, T.A., and Neilsen, D. 2013. The concentration of yeast assimilable nitrogen in Merlot grape juice is increased by N fertilization and reduced irrigation. Canadian Journal of Plant Science 93(1): 37-45. doi:10.4141/cjps2012-092.
  • Hassan, S.E.D., Liu, A., Bittman, S., Forge, T.A., Hunt, D.E., Hijri, M., and St-Arnaud, M. 2013. Impact of 12-year field treatments with organic and inorganic fertilizers on crop productivity and mycorrhizal community structure. Biology and Fertility of Soils. doi: 10.1007/s00374-013-0813-7.


  • Adjunct Professor, Department of Biology, University of British Columbia-Okanagan
  • Test Site Manager, AAFC Minor Use Pesticides Program
  • Society of Nematologists
  • Canadian Phytopathological Society
  • American Phytopathological Society
  • Soil Ecology Society
  • BC Agricultural Climate Adaptation Research Network