Quantitative Serological Estimation of a Hyperparasite: Detection of Verticillium lecanii in Yellow Rust Infected Wheat Leaves by ELISA

Detecting the presence and amount of a fungus in leaf tissue, especially when it is suspected that other fungi are presen~, is quite difficult. Culture methods can be unreliable because a few spores of a fast growing fungus may overgrow other fungi within a, few days (e.g. McKENZIE and HUDSON 1976). Methods which measure the chitin content of fungal walls cannot differentiate between fungi; in addition, recent evidence suggests that there is no direct correlation between the amount of fungal hyphae and the amount of chitin (MAYAMA et al. 1975). Serological tests, because of their high specificity could be a possible solution for these problems. We therefore used the technique of enzyme-linked immunosorbent assay (ELISA), as modified for the detection and identification of plant viruses by CLARK and ADAMS (1977). Since ELISA enables quantitative measurement of antigen we used it to estimate Verticillium lecanii at different stages of infection in leaves of wheat heavily infected with yellow rust (Puccinia striiformis).