Figure 7.

Powdery mildew development on leaves, stems, and flower buds of Cannabis sativa, caused by Golovinomyces cichoracearum. (A) Early stages of infection on young leaf, showing sparse white mycelium on leaf surface. (B) Advanced stages of infection with profuse sporulation, resulting in a powdery appearance on the leaf surface. (C) Development of powdery mildew on leaves and stem of vegetative cuttings of strain “Pink Kush.” (D) Powdery mildew infection on inflorescences of C. sativa “Pink Kush” showing extensive mycelial development. (F) Scanning electron micrograph of mycelium and spores produced on conidiophores developing on the surface of heavily infected leaves. (G) A close-up view of conidiophores with a chain of powdery mildew spores attached. (H) Germination of spores to produce a mycelial network on the leaf surface. (I) Spores of G. cichoracearum adhering to the surface of a glandular trichome on the surface of a leaf bract.