Rhizoctonia solani does not sporulate normally. It can be separated by anamostic grouping. If you are working in hydroponics you may want to make stem isolations which could be used for strain virulence differentiations and determining cultivar or line susceptibility. I believe the reactions might be compared based on length and severity of lesions around a colonized toothpick grown on broth infused sterilize picks which are infused with the rhizoctonia mycelia.

I don't know exactly how you are trying to inoculate the plants, but if you made a suspension and dipped the plant roots in it, possibly it could not infect. Although being soil-borne, the sclerotia might not be able to germinate in the submerged thus anaerobic environment.

Micro injection can infest the seedlings with pathogens