Survival of Macrophomina phaseolina in bean seed and crop residue

The surival of Macrophomina phaseolina in bean seed and crop residue was investigated. Studies on seed infection and survival of the pathogen were conducted in the laboratory. Sterilization of seed or storage for 6 months decreased the number of infected seeds by up to 50%. Seeds from plants with no disease symptoms were 2.5% infected while seeds from severely infected plants had up to 13.5% infection. Survival of the pathogen in crop residue was investigated in field soil in eastern Kenya. Up to 30% of sclerotia were found to be viable after 21 months in field soil. Soil moisture and temperature did not influence survival up to a depth of 20 cm.