Detection and recovery of Rhizoctonia solani in naturally infested glasshouse soils using a combined baiting, double monoclonal antibody ELISA

A combined baiting, double monoclonal antibody immunoassay was developed th at allows specific and sensitive detection of the economically important so il-borne plant pathogen Rhizoctonia solani in naturally infested soils. The assay is quick, taking only three days to complete from receipt of soil sa mples and the immunoassay format allows recovery of Rhizoctonia isolates fr om colonized baits for determination of anastomosis group (AG) affiliation and pathogenicity. The assay was tested on naturally infested soils from co mmercial glasshouses used to grow lettuce. Using the immunoassay, conventio nal anastomosis tests against known AG isolates, and pathogenicity tests, i t was shown that R. solani isolates recovered from soil samples were pathog enic towards lettuce and belonged to AG4. Furthermore, those isolates that exhibited strong pathogenicity towards lettuce were recovered from sites th at had experienced severe Rhizoctonia damage in previous lettuce crops. The possibility of developing a preplanting test to predict damage to specific crop plants due to the presence of particular AGs in the soil is discussed .