What are Hop latent viroid symptoms in cannabis plants?

The cannabis business is affected by hop latent viroid (HLVd), a widespread and financially destructive disease. This pathogen is a severe threat to cannabis crops, causing reduced flower size and THC concentration, and significantly lowering the value of affected harvests. 

Hop latent viroid has emerged as a cannabis pandemic, having been detected in approximately 73% of facilities across the United States, Canada, and Europe. To limit the harmful effects of HLVd, the best prevention is early detection of symptoms and routine pathogen testing. 

Below are HLVD symptoms and their impact, for a more extensive description read Everything you need to know about Hop Latent Viroid.

Asymptomatic presentation

One of the most challenging aspects of HLVd is its ability to present asymptomatically, especially in newly infected plants or during vegetative growth. These plants may carry the viroid without exhibiting symptoms, or only display symptoms when the plant is under stress. symptomatic plants can readily spread the infection, emphasizing the importance of preventative measures.

Growth symptoms

Altered growth patterns

HLVd can disrupt the normal growth patterns of infected plants. These plants may exhibit stunted growth and increased lateral branching, resulting in brittle branches that break easily. By closely monitoring the growth patterns, cultivators can identify potential HLVd infections and take timely action to prevent spread.

Images from Dark Heart Nursery and Cannabis Business Times

Leaf symptoms

Abnormal leaf shape and color

Infected cannabis plants may display distorted leaf shapes and unusual coloration. Leaves might become deformed, twisted, or chlorotic. These visual cues can help identify potential HLVd infections, although it's important to note that not all infected plants show identifiable leaf symptoms.

Flower symptoms

Impacted flower content and quality

HLVd affects the content and quality of cannabis flowers. Infected plants may produce flowers with altered chemical profiles and reduced levels of cannabinoids and terpenes. This decrease in THC concentration compromises the overall marketability and medicinal effectiveness of the harvested cannabis.

Reduced flower size

A considerable decrease in flower size is one of the most visible indicators of HLVd infection. Infected plants tend to produce smaller buds/flowers and trichomes, which significantly reduces their market value. This decline in quality can result in substantial financial losses for cannabis cultivators.

Images from Dark Heart Nursery

Additional symptoms

Poor root growth and increased susceptibility to infection

HLVd can reduce the growth rate and strength of roots, leading to poor rooting and death of newly planted clones. Additionally, HLVd can increase the symptom severity of other cannabis pathogens such as Fusarium and Powdery Mildew.

The significance of early recognition and regular pathogen testing

Identifying infection based solely on HLVd symptoms is unreliable due to its asymptomatic nature. To ensure accurate diagnosis, it is important to screen with regular testing. These tests can detect hop latent viroid before symptoms, allowing identification of sick plants before the infection spreads.  By implementing regular pathogen testing, cultivators can adopt a proactive approach to disease management, preventing the spread of HLVd within their facilities and safeguarding their crop's health and value.

For more information on HLVd transmission methods, read How does Hop latent viroid spread between cannabis plants?

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About TUMI Genomics

TUMI Genomics is advancing cannabis cultivation by bringing biological insights to help commercial growers thrive. Through comprehensive preventative solutions, superior pathogen diagnostics, and AI-driven insights, TUMI Genomics is helping cultivators start clean and stay clean. The unrivaled diagnostics, transparent validation and industry-leading pathogen detection innovations provided by TUMI Genomics are raising the standards of commercial cannabis cultivation. The team at TUMI Genomics is composed of deeply experienced Ph.D. molecular biologists, bioinformaticians, business strategists, and accomplished serial entrepreneurs.

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