Effect of ultraviolet (UV-B) irradiation on infection of roses by Diplocarpon rosae wolf

Abstract

Rose plants and conidia of Diplocarpon rosae were not affected by a 4-fold increase over ambient UV-B (280–320 nm). This high level of UV-B radiation between 6 and 18 hr after a drop of inoculum was placed on leaves decreased infection. The sensitive entity was the conidium germ tube before it penetrated the leaf.