Assessing the Direct Effect of Disease-Suppressive Soil Amendments on Rhizoctonia solani

Project Overview

Project Type: Graduate Student
Funds awarded in 2010: $9,430.00
Projected End Date: 12/31/2011
Grant Recipient: University of Maine
Region: Northeast
State: Maine
Graduate Student:
Faculty Advisor:
Stellos Tavantzis
University of Maine

Annual Reports


  • Agronomic: potatoes, rapeseed


  • Crop Production: biological inoculants, crop rotation
  • Education and Training: extension, farmer to farmer, on-farm/ranch research
  • Pest Management: biological control, competition, field monitoring/scouting
  • Production Systems: agroecosystems, organic agriculture
  • Soil Management: organic matter, soil analysis, soil microbiology

    Proposal abstract:

    Rhizoctonia solani is an important soil-borne pathogen of many crops, including wheat, rice, corn and potatoes. R. solani causes two types of symptoms in potato; stem canker and black scurf of tubers. Soil conditions in Maine and other parts of New England, because of their cool and wet climate during the growing season, are extremely favorable to the fungus and rhizoctonia disease development. Control has traditionally been achieved by the use of chemical seed treatments, which can also kill resident rhizosphere microbial populations. However, the discovery of a non disease-causing, “hypovirulent” isolate of R. solani and its potential as a biocontrol agent presents an attractive alternative to traditional methods of control. The results of recent field trials we have conducted have raised questions about the true effects of specific soil amendments on R. solani in the field. The data shows soil amendments and rotation crops had different effects on yield and tuber diseases of potato over the course of the three year study. The most pertinent questions are how R. solani is directly affected by disease-suppressive management practices during the growing season and how the possible changes in R. solani levels impact tuber yield and diseases. This proposal suggests using current molecular biology techniques to quantify the levels of R. solani in potato soils collected from recent field trials incorporating various disease-suppressive soil amendments.

    Project objectives from proposal:

    1.Monitor Rhizoctonia solani levels in the soils over the course of the growing season in response to the soil amendments described above.

    2.Correlate Rhizoctonia solani levels in the soil with observed tuber diseases and tuber yield data.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.