Diseases are a major concern for greenhouse hemp growers, and they can be a factor that limits the profitable production of plants. The warm, humid greenhouse environment provides optimal conditions for reproduction of many pathogens.
A good sanitation program can help reduce the need for chemical controls, which are a limited option for hemp growers and can improve the effectiveness of other practices for managing diseases.
- Discard plants that are heavily infected and those with untreatable diseases such as root rots (Figure 1).
- Isolate plants infected with treatable diseases until disease is eliminated.
- Prune or remove infected tissues to reduce sources for spore production or propagule multiplication.
- Discard prunings and culled plants immediately. Infected plant material should be buried, burned, or placed in cull piles (minimum 100 yds. from greenhouse). Do not compost diseased plant material.
- Remove weeds and volunteer plants to limit alternate hosts and disease spread.
- Do not reuse soil or potting media.
- Do not bring outside soil into the greenhouse.
- Disinfest pots, benches, floors, and tools to remove spores and propagules.
- Clean excess soil and plant debris from floors and benches.
- Cover dirt walkways with gravel, concrete, or landscape cloth.
- Do not drag hoses and other tools along floors, where infested soil and plant debris can stick and be moved.
- Empty the greenhouse between seasons or crops and clean and sanitize all surfaces.
- Use footbaths containing sanitizers to prevent movement of propagules to clean areas.