Botrytis bud rot, powdery mildew, root rots and hop latent viroid cause some of the biggest losses in cannabis production. Because chemical options for cannabis are limited, researchers focus on prevention and integrated management.
Two reviews from Simon Fraser University lay out the current picture. Indoor and greenhouse grows share many of the same diseases, and the strongest defenses start before a single flower forms: disease-tolerant genetics, clean mother plants, sanitation, good irrigation practice, regular monitoring and climate control.
Post-harvest matters too. In one drying study, buds dried the traditional way were heavily infested with Alternaria mold, while controlled-atmosphere drying reduced that risk.
Gaps we’re still filling: controlled trials of specific pest treatments on cannabis, such as predatory insects and insecticidal soaps.
Key terms
Hop latent viroid
A tiny infectious RNA that stunts cannabis and reduces yield, often without obvious early symptoms. It spreads readily through cuttings from infected mother plants.
Studies
4 studies
Integrated Management of Pathogens and Microbes in Cannabis sativa L. (Cannabis) under Greenhouse Conditions
Plants · 2024
Drug-type cannabis
Review
Open access
Clean mother plants and disease-tolerant genetics are the foundation of disease control.
Authors: Liam Buirs, Zamir K. Punja
13(6):786
Study plant: Review focused on high-THC cannabis grown in greenhouses
This review lays out an integrated plan for managing greenhouse cannabis diseases, including root rots (Fusarium and Pythium), bud rot (Botrytis), powdery mildew and hop latent viroid, at each stage from mother plants through cuttings, veg and flower. It stresses disease-tolerant genetics and pathogen-free stock plants, combined with sanitation, irrigation management, monitoring and climate control.
Emerging diseases of Cannabis sativa and sustainable management
Pest Management Science · 2021
Mixed / review
Review
Open access
Indoor and greenhouse grows share many of the same major diseases, and sustainable controls are the focus.
Authors: Zamir K. Punja
77(9):3857–3870
Study plant: Review of diseases reported in North American cannabis and hemp production
A review of the diseases currently affecting cannabis and hemp production in North America, covering newly characterized pathogens reported from 2017 to 2020, including Botrytis bud rot, powdery mildew and hop latent viroid. It emphasizes sustainable control using biological products and reduced-risk options, and notes that indoor and greenhouse crops share more diseases with each other than with field-grown plants.
Postharvest Drying and Curing Affect Cannabinoid Contents and Microbial Levels in Industrial Hemp (Cannabis sativa L.)
Plants · 2025
Hemp
Controlled experiment
Open access
Fast hot-air drying cut mold counts and didn’t reduce total cannabinoids.
Authors: Yousoon Baek, Heather Grab, Chang Chen
14(3):414
Study plant: Two cannabinoid-type hemp cultivars (‘Hempress’ and ‘Wild Bourbon’)
Freshly harvested flower from two hemp cultivars was dried three ways (hot air at 75 °C, ambient air at 25 °C, or freeze-drying) and then cured in different containers. Hot air took the flower from 77% to 6% moisture in 8 hours and cut yeast and mold counts by up to 99%. Ambient drying took a week and freeze-drying a day. Total cannabinoids didn’t change significantly with drying or curing method, though some acid cannabinoids converted to their neutral forms. The authors favored hot-air drying followed by glass-jar curing.
In Pursuit of Optimal Quality: Cultivar-Specific Drying Approaches for Medicinal Cannabis
Plants · 2024
Drug-type cannabis
Controlled experiment
Open access
Controlled-atmosphere chambers dried at least 60% faster, kept terpenes, and reduced mold seen with traditional drying.
Authors: Matan Birenboim, Nimrod Brikenstein, Danielle Duanis-Assaf, Dalia Maurer et al.
13(7):1049
Study plant: Two medicinal chemovars (a high-THC ‘240’ and a hybrid ‘Gen12’)
Two chemovars were dried in controlled-atmosphere chambers with different gas mixes, including nitrogen-rich and low-oxygen blends, and compared with traditional drying. The chambers cut drying and curing time by at least 60% while preserving terpenes. Traditionally dried buds were heavily infested with Alternaria mold and showed some Botrytis. The best gas mix differed by chemovar and by terpene type.