Histopathology of S. tanaceti infection in pyrethrum leaf lamina

Abstract

The infection process and life cycle of S. tanaceti in leaf lamina of pyrethrum plants was investigated using histopathology. Conidia attached firmly to the leaf surface before the infection hyphae penetrated directly into the epidermal cells of the leaf without forming appressoria. The maximum germination of conidia on leaf surface was 85 % at 54 HAI. Infection hyphae infected the epidermal and palisade parenchyma cells through the middle lamella. Brown lesions on the leaf were a result of infected necrotic epidermal cells. Extensive colonization through both intra- and intercellular hyphae along with pycnidia formation caused enormous damage to the infected cells at 12 DAI. Unlike the quad..