Evaluación del efecto biocontrolador de Rhizoctonia de orquídeas sobre Rhizoctonia solani kühn patogeno del suelo en arroz (Oryza sativa l.)

Soil fungi have varied trophic strategies, allowing them to interact with plants as saprotrophs, mutualists, pathogens, and biocontrol agents. The form-genus Rhizoctonia, with teleomorphs in Ceratobasidium, Tulasnella, Thanatephorus and Sebacina, can fill all these roles. It is mycorrhizal in orchids and pathogenic in important crops such as rice, in which R. solani Kühn causes sheath blight. Management of sheath blight is based on the use of synthetic fungicides and varietal resistance, but there are promising results on the use of fungi for biocontrol. There is a need for integrated pest management using binucleate isolates of Rhizoctonia for biocontrol of pathogenic fungi in the soil. In this project I evaluated the potential for biocontrol of R. solani on rice by binucleate Rhizoctonia isolated from orchid roots. The objectives were: 1) identify isolates of the formgenus Rhizoctonia from roots of orchids from different habitats; 2) evaluate their patogenicity on a different host, in this case rice; 3) test their potential for biocontrol of R. solani in rice; 4) determine the effect of different doses of nitrogen, as well as pasteurized vs. unpasteurized soil, on the pathogenicity and biocontrol activity of Rhizoctonia.