Effect of Plant Species on Persistence of Paecilomyces lilacinus Strain 251 in Soil and on Root Colonization by the Fungus

The effect of 12 plant species on the persistence of Paecilomyces lilacinus strain 251 in soil was investigated. After incorporating formulated conidia into non-sterile soil followed by transplanting different test plants, the population dynamic of the fungus was determined over 100 days. At termination of the experiment, the fungal population in the planted soil was compared to the density of P. lilacinus in the rhizosphere and the percent increase or decrease was calculated for each crop. In addition, the potential of P. lilacinus strain 251 to colonize roots endophytically was investigated. Comparison of the slopes describing the population dynamics of the fungus showed no significant differences between soil without plants and soil from the root zone of the majority of the test plants. Bean was the only plant species consistently exerting a negative effect on the persistence of P. lilacinus strain 251 in the soil. For the first time, P. lilacinus strain 251 was isolated in significant numbers from healthy root tissue of barley plants.