Level of inoculum suitable for studies on the relationship of coffee seedlings and Rhizoctonia solani or Myrothecium roridum

Abstract

Suitable levels of inoculum of Rhizoctonia solani and Myrothecium roridum for the induction of symptoms in coffee (Coffea arabica L.) seedlings were determined in greenhouse tests based on the percentage of seedling mortality and disease incidence. Best inoculum level for R. solani and M. roridum was 15 and 10%, respectively. Myrothecium roridum was more virulent than R. solani, and thus caused higher mortality of coffee seedlings. For both pathogens, as the inoculum concentration increased, the dry weight of plants decreased. A direct positive relation between incidence of the disease and concentration of the inoculum was detected, it was found that R. solani is more persistent than M. roridum in the inoculated soil.