Emerging diseases of Cannabis sativa and sustainable management

[VOSTOK]

Overview of a cannabis propagation and cultivation scheme. (A) Stock (mother plant) provides a source of cuttings. ( Rooted cuttings in propagation room. © Vegetative plants from cuttings. (D) Plants in flower room. (E) Flowering plants under 12:12 h photoperiod. (F) Plant approaching harvest. (G) Intact inflorescences in the drying room. (H) Detached dried buds. (I) Dried buds at packaging. (J) Indoor production facility. (K) Outdoor production in plastic tunnel. (L) Field production on plastic mulch. 

 

Abstract

 

Cultivation of cannabis plants (Cannabis sativa L., marijuana) has taken place worldwide for centuries. In Canada, legalization of cannabis in October 2018 for the medicinal and recreational markets has spurned interest in large-scale growing. This increased production has seen a rise in the incidence and severity of plant pathogens, causing a range of previously unreported diseases. The objective of this review is to highlight the important diseases currently affecting the cannabis and hemp industries in North America and to discuss various mitigation strategies. Progress in molecular diagnostics for pathogen identification and determining inoculum sources and methods of pathogen spread have provided useful insights. Sustainable disease management approaches include establishing clean planting stock, modifying environmental conditions to reduce pathogen development, implementing sanitation measures, and applying fungal and bacterial biological control agents. 

The emerging pathogens on cannabis and hemp plants. Pathogens shown in bold are the most damaging.

 

CONCLUSIONS AND FUTURE PERSPECTIVES

Over the past 4 years, a large number of fungal, viral, bacterial and nematode pathogens have been reported to cause diseases on cannabis and hemp crops in North America. This review has attempted to summarize these diseases and discuss mitigation approaches utilizing a number of strategies. The recent lifting of restrictions on the cultivation of these crops in North America will encourage peer-reviewed research to be conducted. The implementation of certified pathogen-free planting material is an important first step, followed by the utility of biological control agents, which still require research to determine their comparative efficacies and modes of action. The registration of selective fungicides to combat pathogens during the propagative stage should be addressed, with zero residue limits imposed prior to harvest of the final product.

 

HERE: https://onlinelibrary.wiley.com/doi/10.1002/ps.6307