Symptoms of Hop Latent Viroid (HLVd)
Professor DeBacco

CannaMed23 Presentation
Medicinal Genomics. (2023a, June 8). Understanding and Managing HOP latent viroid in cannabis - Zamir Punja, PhD [Video]. YouTube.    • Understanding and Managing Hop Latent...  

Looks Can Vary
Two cannabis plants infected with the same viroid can have a wide degree of different visual symptoms.
To catch it early does take a trained eye.

Stage of Development Has an Impact
What symptoms you may see are in part dependent on the stage of development of the plant and when (and where physically on the plant) the point of infection may have occurred.

Common Symptoms
Slow growth (stunting via shorter internode spacing)
Leaf malformations
Leaf chlorosis
Can mimic iron deficiency
Brittle stems
Reduced root formation
Horizontal growth that then grows up like an exponential curve
Greater leaf overlap
Reduced water intake
*Flower destruction (smaller and less dense = reduced yield)
Stem/Node Swelling

Confirmed Case of HLVd
May not commonly reported, but does happen

Can Vary Greatly in the Plant
This is why when sampling different portions of the plant should be taken.

Special attention to the roots as HLVd can initially accumulate in this area.
Can Vary By Cultivar
While no cultivars have been show to be completely resistant to HLVd, there are some early data indicators that some may be more tolerant.

This could be potentially used as part of a breeding program is this can show consistency.

Trichome Change
Reduced in size and shape
This directly impacts the compounds that the plant can produce
The numbers of trichomes are the same (top image) but the structure is what is different
The infected trichomes are underdeveloped

Impact Varies by Cultivar
Unfortunately it is really a matter of how much is the plant cannabinoids reduced.

Link to Lecture Slides: https://drive.google.com/file/d/1eOJS...

*Due to the description character limit the full work cited for "Symptoms of Hop Latent Viroid (HLVd)" can be viewed at... https://docs.google.com/document/d/12...