Alexandra  Stone


plant pathology
cover cropping
biological control
web 2.0
organic agriculture
reduced tillage
participatory research
Alexandra Stone
Associate Professor, Vegetable Cropping Systems Specialist

I work with Oregon conventional and organic vegetable farmers on cultural and biological control of plant diseases (corn root rot, bean mold, cucurbit wilt, clubroot) and cover cropping. I also work with the Oregon Processed Vegetable Commission on its sustainability initiative, with a current focus on wildife habitat conservation on Willamette Valley farms.

I lead  and am a leadership team member of eOrganic, the Organic Agriculture resource area for eXtension. Find us at and

I produced Weed 'Em and Reap, which is a 2-DVD series of videos highlighting farmers and researchers working on non-chemical weed management and reduced tillage strategies. You can find all of the Weed 'em and Reap videos at  and at eOrganic's YouTube site.

OSU Campus
Department of Horticulture
4017 Ag and Life Sciences Bldg
Corvallis, OR 97331-7304
United States
(541) 602-4676


I have been investigating the use of the biological control agent commercially available as Contans (Coniothyrium minitans) as a control for white mold of vegetables, especially snap beans grown by processed vegetable growers. This project has been supported by grants from Western SARE, Western Region IPM, and the Oregon Processed Vegetable Commission.

I am working on identifying the cause of cucurbit wilt (with Ken Johnson and the Plant Clinic, OSU Botany and Plant Pathology) and finding solutions to other production problems (fruit rots, storage quality) associated with the production of cucurbit crops (Golden Delicious, other winter squash, cucumbers) in western Oregon. This project is supported by a grant from Western SARE.

I am working with Aaron Heinrich and Dan Sullivan on pH management (in combination with cultural practices and biological control) for suppression of clubroot in crucifers. This project has been supported by grants from OSU Ag Research Foundation and the Oregon Processed Vegetable Commission.

I am working on a project with cooperators in Washington and California in which we are describing soil and pest management practices and functions on long term organic farms as well as working to find solutions to their intractable soil and pest problems. This project is supported by a grant from Western SARE.

In the past I have evaluated cover crops and rotation for their potential to suppress root rot of sweet corn; we have shown that oats are the winter cover crop most consistently suppressive and a four rotation reduced root rot severity. This project was supported by the Oregon Processed Vegetable Commission.

A few years ago I worked with others at OSU and 10 or so of Oregon's most experienced organic vegetable farmers on Ospud, a participatory organic potato research and outreach project - learn more at Participatory Organic Potato Project. This project was supported by Western SARE.



I have been the vegetable specialist in the Dept of Horticulture since 2000.

My training: Biology (BS, Dartmouth College, Hanover, NH), Environmental Science (PhD Ohio State University, emphases Plant Pathology and Soil Science), and a postdoctoral project in the Soils Dept at Univ. of WI Madison.

I accept graduate students for Horticulture


Extension Articles

  1. White Mold of Snap Bean and Other Vegetable Crops
  2. What is Wrong with my Potato Tubers?
  3. Organic Management of Late Blight of Potato and Tomato (Phytophthora infestans)
  4. Organic Management of Late Blight of Potato and Tomato with Copper Products
  5. Incorporating High Tunnels into a Diversified Organic Vegetable Farm in Oregon: Case Study of Gathering Together Farm
  6. Organic Seed Resource Guide

Journal Articles

Formiga, A., A. Stone, D. Heleba, J. McQueen, and M. Coe, 2014. Evaluation of the eOrganic webinar program. Journal of Extension. In press.

Stone, A., D. Treadwell, A. Formiga, J. McQueen, M. Wander, J. Riddle, H. Darby, and D. Heleba, 2012. eOrganic: the Organic Agriculture Community of Practice for eXtension. HortTechnology 22(5): 583-588.

Dreves, A.J., D. Dalthorp, A. G. Stone, and G. Fisher, 2006. Spring emergence and seasonal flight of Delia radicum (Diptera: Anthomyiidae) in Western Oregon. Environ. Entomol. 35:465-477.

Cespedes-Leon, M.C., A.G. Stone, and R. P. Dick, 2006. Organic soil amendments: impacts on snap bean common root rot and soil quality.  Appl. Soil Ecol. 31:199-210.

Darby, H.M., A.G. Stone, and R.P. Dick, 2006. Compost and manure mediated impacts on soilborne pathogens and soil quality. Soil Sci.  Soc. Am. J. 70: 347-358.

Rotenberg, D., L.R. Cooperband, and A.G. Stone, 2005. Dynamic relationships between soil properties and foliar disease as affected by annual additions of organic amendment to a sandy-soil vegetable production system. Soil Biol. Biochen. 37(7):1343-1357.

Stone, A.G., S.J. Scheuerell, and H.M. Darby, 2004.Suppression of soilborne diseases in field agricultural systems: organic matter management, cover cropping, and other cultural practices.  In: F. Magdoff and R. Weil, eds., Soil Organic Matter in Sustainable Agriculture. CRC Press. Boca Raton, pp 131-177.

Stone, A.G., G.E. Vallad, L.R. Cooperband, D. Rotenberg, H.M. Darby, R.V. James, W.R. Stevenson, and R.M. Goodman, 2003. The effect of organic amendments on soilborne and foliar diseases in field-grown snap bean and cucumber. Plant Disease 87:1037-1042.

Cooperband, L.R., A.G. Stone, M.R. Fryda, and J.L. Ravet, 2003.Relating compost measures of stability and maturity to plant growth. Comp. Sci. Util. 11(2):113-24.

Stone, A.G., S.J. Traina, and H.A.J. Hoitink, 2001. Particulate organic matter composition and Pythium damping-off of cucumber. Soil Sci. Soc. Am. J. 65:761-770.

Boehm, M.J., T. Wu, A.G. Stone, B. Kraakman, D.A. Iannotti, G.E. Wilson, L.V. Madden and H.A.J. Hoitink, 1997. CP-MAS 13C-NMR spectroscopic characterization of soil organic matter relative to culturable species composition and sustained biological  control of Pythium root rot. Appl. Environ. Microbiol. 63:162-168.

Hoitink, H.A.J., A.G. Stone, and D.Y. Han, 1997. Suppression of plant diseases by composts. HortScience: 32:184-187.


Specialty Seed Crops Resources 

Outreach and Extension

I lead, OSU's vegetable production web portal.  There you can find the Oregon Processed Vegetable Commission website, VegNet, and information on vegetable prodution, sustainability, and wildlife habitat conservation for vegetable growers in Oregon.

I am a member of the leadership team for eOrganic, the national eXtension Community of Practice at and

Links to some of my outreach projects:  (I produced the Weed 'Em and Reap I and II series)

Participatory Organic Potato Project