Powdery Mildew (PM) and Septoria resistance in landraces

Powdery mildew resistance in a Nepali Mountain Ganja landrace (foreground) is shown in the above photo of a test for resistance to powdery mildews.

Powdery mildews are a group of related fungi which attack a wide range of plants, causing a white, dusty coating on leaves, stems and flowers.

Nearly all modern ‘drug-type’ Cannabis strains get obliterated by powdery mildew in field trials.

But several of our accessions of Cannabis landraces showed amazing resistance to PM.

Most impressive was an accession from Chitral, which showed total resistance – i.e., zero infection.

Other excellent performers were Nanda Devi, Nanda Devi #2, Rasoli, Kandahar, Tirah, and Moliotiko.

The best performers against Septoria were Himalayan landraces such as Rasoli and our landraces from Southeast Asia, including the Burmese and the Highland Lao accessions from Bolikhamsai.

Septoria is genus of fungal pathogens that cause leaf spots and can result in foliage loss and stunting. At least one species of Septoria specifically affects cannabis: Septoria cannabis.