Scanning Electron Microscopical Observation and X‐ray Microanalysis of Erysiphe pisi DC on Infected Leaves of Pea (Pisum sativum L)

Observations on scanning electron microscope (SEM) and low vacuum scanning electron microscope (LVSEM) of Erysiphe pisi in infected leaves of pea (Pisum sativum). are reported together with data from X‐ray micro‐analysis. Morphology of ungerminated and germinated conidia was observed and LVSEM revealed halo formation around the penetration peg of the pathogen. X‐ray microanalysis of the composition of halo showed the accumulation of Si and P. Presence of S. Mg, Cl, K and Ca was also discerned. Deposition of Si in the halo and profuse growth of the pathogen indicate that Si deposition is not an essential signal for inducing resistance in the host. LVSEM appears to be a suitable and rapid method to study the morphology as well as halo formation in E. pisi. X‐ray microanalysis and LVSEM studies of E. pisi are reported for the first time.