Definition – What does Powdery Mildew mean?
Powdery mildew is a fungal disease that affects a wide range of plants, including cannabis plants. This disease is caused by multiple different species of fungi in the order of Erysiphales, with Podosphaera xanthii(a.k.a. Sphaerotheca fuliginea) being the most commonly reported cause. Erysiphe cichoracearum was formerly reported to be the primary causal organism throughout most of the world.
PM is one of the easiest plant diseases to identify because the symptoms shown are quite distinctive. Infected plants display white powdery spots on the leaves and stems. The lower leaves are the most affected, but the mildew can appear on any above-ground part of the plant. As the disease progresses, the spots get larger and denser as large numbers of asexual spores are formed, and the mildew may spread up and down the length of the plant.
Powdery mildew fungi can reproduce both sexually and asexually. This fungi releases it’s matured spores in order to find new areas to grow on (i.e. your plant).
Powdery mildew spores are most often spread via airborne transmission, but also can hitchhike on a number of things including common garden pests, pets or even on your clothes.
If you’re walking in and out of your growroom a lot, and you just can’t seem to get rid of powdery mildew even after mulitple treatments, it’s probable that you’re bringing it in.
- Powdery mildew sucks the life out of plants, robbing them of their ability to collect nutrients via leaves. As PM takes over, the leaves unable to collect nutrients will yellow, bringing the plant into a slow stunted growth.
- PM spreads quickly though cannabis, smothering it in white mildew – many times in just a few days. Left untreated, powdery mildew will effectively ruin your weed harvest.
- Cannabis plants afflicted with powdery mildew should not be harvested for smoking – inhaling fungi is not good.