Plant Pathology

Research Projects

Population Genetics | Ecology and Epidemiology | Sustainable Agriculture

Sustainable Agriculture

Influence of microbial species and functional diversity in soils on pathogen dispersal and ecosystem processes in organic and conventional agroecosystems.

Fig. 1. White mycelial growth and brown lesion at the base
of a pepper stem infected with Sclerotium rolfsii.

A grant was funded by the USDA Southern SARE program to examine the influence of microbial species and functional diversity and composition on the invasion of soils from conventional and organic agroecosystems by the Basidiomycete plant pathogen Sclerotium rolfisii causal agent of Southern blight. We are examining the spatial dynamics of disease spread by S. rolfsii in plots amended with either organic or synthetic fertiltity amendments.

Fig. 2. Students and visiting scientists learn about organic production systems at Stephan Hartmann's Black River Organic farm.

We are also sampling soils on organic and conventional farms that have received organic or conventional soil fertility amendments and comparing disease suppressiveness of these soils in order to determine the functional components of soil microbial communities associated with disease suppression.

Select papers

1. Liu, B, C. Tu, Hu, S., Gumpertz, M. L., and Ristaino, J. B. 2007. Long-term effects of organic and synthetic soils fertility amendments on soil microbial communities and the development of southern blight. Soil Biol Biochem. 39:2302-2316

2. Liu, B, C. Tu, Hu, S., Gumpertz, M. L., and Ristaino, J. B. 2007. Effect of organic, sustainable, and conventional management strategies in grower fields on soil physical, chemical, and biological factors and the incidence of Southern blight. Appl. Soil Ecol. DOI: 10.1016/j.apsoil.2007.06.007.

3. Bulluck, L. R., Evanylou, G. K., and Ristaino, J. B. 2002. Influence of Alternative and Synthetic Soil Fertility Amendments on Soil Microbial Communities and Physical and Chemical Properties on Organic and Conventional Farms. Appl. Soil. Ecol. 19:147-160.

4. Bulluck, L. R., and Ristaino, J. B. 2002. Synthetic and organic amendments affect Southern blight, soil microbial communities and yield of processing tomatoes. Phytopathology 92:181-189.

5. Bulluck, L. R., Barker, K. R., and Ristaino, J. B. 2002. Nematode trophic group and community dynamics on tomato as influenced by organic and synthetic soil fertility amendments. Appl. Soil Ecol. 21:233-255.