Updated: Nov 5
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A 2023 study entitled "Hop Latent Viroid: A Hidden Threat to the Cannabis Industry" that was published in the journal Viruses aimed to "summarize all of the scientific information available on Hop Latent Viroid (HLVd) so as to be able to understand the effect of HLVd on yield loss, cannabinoid content, terpene profile, and disease management and to develop crop protection strategies."
Hop Latent Viroid: Cannabis Industry Threat Study
Hop Latent Viroid: Cannabis Industry Threat. The research reported that a 2021 survey conducted by Dark Heart Nursery Research that involved 200,000 cannabis tissue samples concluded that "90 percent of cannabis-growing facilities in California were contaminated with HLVd."
"HLVd infestations can also negatively affect the vigor and yield of cannabis plants and this could result in industry losses of up to four billion USD annually."
The scientists explained that the "duds" disease of cannabis, first detected as recently as 2019, is currently the most devastating. "The causative agent of this disease was found to be HLVd," they wrote. The study estimated that HLVd infestations can also negatively affect the vigor and yield of cannabis plants and that this could result in industry losses of up to four billion USD annually.
The study cited other research that found that HLVd-infected cannabis plants could suffer a significant reduction in THC yield of 50-70 percent, resulting in markedly lower revenues from these crops.
Hop Latent Viroid: Cannabis Industry Threat Study Conclusions
Hop Latent Viroid: Cannabis Industry Threat. The study's authors made the following conclusions based on their scientific investigation:
"Although HLVd infection was first reported in hop plants in 1988, both the scientific community and stakeholders prioritized research on HSVd which caused more severe visible disease symptoms in infected hop plants than did HLVd. However, scientific data on the negative effects of HLVd on both the α-bitter acid and terpene contents in both symptomatic and asymptomatic hop collected over the years have attracted the attention of researchers in recent years.
"Further studies are required to understand whether both of the HLVd sequence variants are able to infect and induce disease symptoms in cannabis plants."
"The effect of HLVd on asymptomatic hop plants is supported by recent transcriptomic studies conducted on hop plants co-inoculated with HLVd and CBCVd aimed at understanding the increased aggravation of the CBCVd-induced disease symptoms in the presence of HLVd.
"Although two HLVd sequence variants were detected in cannabis plants, it is not clear whether the identified sequence variants are the result of viroid quasi-species or true dominant HLVd variants. Hence, further studies are required in order to understand whether or not both of the HLVd sequence variants are able to infect and induce disease symptoms in cannabis plants. If so, what are the HLVd sequence variant-specific disease symptoms on the susceptible cannabis plant and HLVd variant-specific effect on the cannabinoids.
"These studies will help in understanding the HLVd 'master sequence' that cause the initial infection in cannabis plants, and in the study of the HLVd-cannabis host interaction. Additionally, it would be interesting to understand the role of the U225A mutation located in the lower pathogenicity domain in both HLVd’s pathogenicity and its adaptability to cannabis plants. Since HSVd, AFCVd, and CBCVd are all infectious to hop plants, it is worth conducting a bioassay on cannabis plants and preparing to contain them all if any infection is found.
"HLVd-resistant cannabis cultivars are not known. Meristem tissue culture is the only effective control method that can save plants. This process is both laborious and expensive."
"To date, HLVd-resistant cannabis cultivars are not known. Meristem tissue culture is the only effective control method via which infected plants can be saved. This process is both laborious and expensive. Although tissue-cultured plantlets are viroid-free, it is important to understand that they are not viroid-resistant. Hence, following preventive measures in order to avoid an insurge of HLVd into a given growth environment is crucial in HLVd-associated disease management.
"However, for sustainability reasons, it is important to find a practical long-term solution by employing strategies such as the control of HLVd infection by breeding HLVd-resistant plants, by cross-protection, and by developing RNA interference-mediated resistance in the plants."
View the original study.
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