Uploaded August 2025 | Updated September 2026, 2 weeks ago
Tags: HLVd, Hop Latent Viroid, Hop Latent Viroid Disease, Cannabis Yield, Cannabinoid Production, Pest Management
Dr. Punya Nachappa, Associate Professor at @ColoradoStateUniversity, presents "Biology and Management of Hop Latent Viroid" at CannMed 2025.
Hop latent viroid (HLVd) is an emerging pathogen affecting hemp with potential to cause significant damage and crop loss. Since its initial detection in California in 2019, HLVd has been detected in all major hemp growing states including Colorado, Oregon, Washington and in Canada. There is limited information on the impact of HLVd on hemp biomass and yield whereas there is accumulating evidence that HLVd reduces cannabinoid levels in cannabis. HLVd is known to be transmitted mechanically to plants, however there is little information known about other transmission routes including possible arthropod vectors.
Here, we investigated the impact of HLVd on hemp biomass, inflorescence, seed yield and cannabinoid levels, the ability of hemp pests, cannabis aphids and wester flower thrips to transmit HLVd, and the effect of chemical elicitors in reducing HLVd infection levels. HLVd did not have an impact on hemp biomass and yield, but it decreased levels of certain cannabinoids such as THC. We found that cannabis aphids and thrips are able to acquire HLVd as soon as 5 minutes and maintain HLVd for several hours. Transmission assay results indicate cannabis aphids and thrips were able to transmit HLVd in hemp at a low percentage (24% and 14%, respectively). Certain chemical elicitors showed significant reduction in viroid titers compared to control treatments. Beyond potential viroid reduction, chemical elicitors such as salicylic acid, brassinolides (BR), and 6-benzylaminopurine (BAP) significantly increased biomass and flower production. However, SA, BR, TRIA, chlormequat chloride (CCC), and methyl jasmonate (MeJA) also reduced key cannabinoid levels, notably THC and CBD, highlighting the complexity of using chemical elicitors to control HLVd. Overall, this research developed new knowledge regarding HLVd, in an effort to manage and reduce losses to the hemp and cannabis industry in the U.S and worldwide.
Learning Objectives:
⦾ Assess the impact of HLVd on hemp yield and cannabinoids
⦾ Compare HLVd acquisition and transmission by two major cannabis pests, cannabis aphids and thrips
⦾ Evaluate the efficacy of various chemical elicitors in reducing HLVd infection
0:00 - Introduction to Hop Latent Viroid
0:26 - Acknowledging Funding and Collaborators
1:00 - The State of Hemp in the US
2:10 - Published Viruses and Viroids in Hemp
2:54 - HLVd: Impact on Hemp vs. Cannabis
4:29 - Research Goals: Host and Vector Transmission
5:27 - Study on HLVd's Impact on Hemp Biomass
7:50 - Screening Different Hemp Genotypes
8:59 - Minimal Impact on Field-Grown Hemp
9:16 - Understanding Insect Vector Transmission
11:59 - Common Hemp Pests and Their Feeding Habits
12:40 - Conducting Virus Acquisition & Transmission Assays
15:18 - HLVd Does Not Replicate in Insects
17:04 - Transmission Efficiency of Aphids and Thrips
17:54 - Testing the Efficacy of Chemical Elicitors
21:38 - Increased Yield vs. Reduced Cannabinoids
22:55 - Summary of HLVd Research Findings
23:50 - Educational Resources and Outreach
Learn More about CannMed: cannmedevents.com
Sign Up for Our Newsletter: share.hsforms.com/1oi57oJDnRN-Uqqc9YPByRA20xr2
The CannMed 25 Innovation & Investment Summit showcased its first international venue, the Wyndham Grand Rio Mar Golf & Beach Resort in Puerto Rico from June 17 - 20, 2025. Since its inception at Harvard Medical School in 2016, CannMed has earned a reputation as the premier destination for cutting-edge research, emerging technologies, and investment opportunities. CannMed 25 continues this tradition with medicinal plant researchers, clinicians and venture capitalists who view this Summit as the industry’s number one showcase for the latest advances in plant-based science, medicine, cultivation, and safety.
Tags: HLVd, Hop Latent Viroid, Hop Latent Viroid Disease, Cannabis Yield, Cannabinoid Production, Pest Management
Dr. Punya Nachappa, Associate Professor at @ColoradoStateUniversity, presents "Biology and Management of Hop Latent Viroid" at CannMed 2025.
Hop latent viroid (HLVd) is an emerging pathogen affecting hemp with potential to cause significant damage and crop loss. Since its initial detection in California in 2019, HLVd has been detected in all major hemp growing states including Colorado, Oregon, Washington and in Canada. There is limited information on the impact of HLVd on hemp biomass and yield whereas there is accumulating evidence that HLVd reduces cannabinoid levels in cannabis. HLVd is known to be transmitted mechanically to plants, however there is little information known about other transmission routes including possible arthropod vectors.
Here, we investigated the impact of HLVd on hemp biomass, inflorescence, seed yield and cannabinoid levels, the ability of hemp pests, cannabis aphids and wester flower thrips to transmit HLVd, and the effect of chemical elicitors in reducing HLVd infection levels. HLVd did not have an impact on hemp biomass and yield, but it decreased levels of certain cannabinoids such as THC. We found that cannabis aphids and thrips are able to acquire HLVd as soon as 5 minutes and maintain HLVd for several hours. Transmission assay results indicate cannabis aphids and thrips were able to transmit HLVd in hemp at a low percentage (24% and 14%, respectively). Certain chemical elicitors showed significant reduction in viroid titers compared to control treatments. Beyond potential viroid reduction, chemical elicitors such as salicylic acid, brassinolides (BR), and 6-benzylaminopurine (BAP) significantly increased biomass and flower production. However, SA, BR, TRIA, chlormequat chloride (CCC), and methyl jasmonate (MeJA) also reduced key cannabinoid levels, notably THC and CBD, highlighting the complexity of using chemical elicitors to control HLVd. Overall, this research developed new knowledge regarding HLVd, in an effort to manage and reduce losses to the hemp and cannabis industry in the U.S and worldwide.
Learning Objectives:
⦾ Assess the impact of HLVd on hemp yield and cannabinoids
⦾ Compare HLVd acquisition and transmission by two major cannabis pests, cannabis aphids and thrips
⦾ Evaluate the efficacy of various chemical elicitors in reducing HLVd infection
0:00 - Introduction to Hop Latent Viroid
0:26 - Acknowledging Funding and Collaborators
1:00 - The State of Hemp in the US
2:10 - Published Viruses and Viroids in Hemp
2:54 - HLVd: Impact on Hemp vs. Cannabis
4:29 - Research Goals: Host and Vector Transmission
5:27 - Study on HLVd's Impact on Hemp Biomass
7:50 - Screening Different Hemp Genotypes
8:59 - Minimal Impact on Field-Grown Hemp
9:16 - Understanding Insect Vector Transmission
11:59 - Common Hemp Pests and Their Feeding Habits
12:40 - Conducting Virus Acquisition & Transmission Assays
15:18 - HLVd Does Not Replicate in Insects
17:04 - Transmission Efficiency of Aphids and Thrips
17:54 - Testing the Efficacy of Chemical Elicitors
21:38 - Increased Yield vs. Reduced Cannabinoids
22:55 - Summary of HLVd Research Findings
23:50 - Educational Resources and Outreach
Learn More about CannMed: cannmedevents.com
Sign Up for Our Newsletter: share.hsforms.com/1oi57oJDnRN-Uqqc9YPByRA20xr2
The CannMed 25 Innovation & Investment Summit showcased its first international venue, the Wyndham Grand Rio Mar Golf & Beach Resort in Puerto Rico from June 17 - 20, 2025. Since its inception at Harvard Medical School in 2016, CannMed has earned a reputation as the premier destination for cutting-edge research, emerging technologies, and investment opportunities. CannMed 25 continues this tradition with medicinal plant researchers, clinicians and venture capitalists who view this Summit as the industry’s number one showcase for the latest advances in plant-based science, medicine, cultivation, and safety.
