Uploaded August 2023 | Updated September 2026, 2 weeks ago
Hope Going Forward with Hop Latent Viroid (HLVd)
Professor DeBacco
Is it Getting Worse?
Hard to tell, if the viroid is spreading or if the awareness is spreading resulting in more growers looking for it and finding it.
Why Should I Be Concerned?
Reduced yields
Pathogen spreading
No cure
Being Aware
Know what to look for and do not be afraid to test your plants.
(Carefully) tell others you may know if you think their plants may be showing symptoms and encourage them to get their plants tested.
“Unclean” Grower
If you have plants that test positive it is not an indication of bad practices.
Valuing Testing
Seed testing
Clone testing
Asking for screening reports
Finding Resistant Cultivars
To date, no cannabis cultivars are known to be resistant to HLVd.
However, remember this is still a new disease and more cultivators are now aware of it and will be actively seeking a possible resistant variety.
Sanitation Protocols
Being aware of workers
Limit contact with known infected plants
Know who was around an infected plant
Follow sanitation protocols with products that actually work against HLVd.
This is a Problem, but Research is on Going
Sharing of information both at Universities and also companies.
Link to Lecture Slides: drive.google.com/file/d/1RbFjirLoxOmyWcevdsIlZMmOoF9xb73x/view?usp=drive_link
*Due to the description character limit the full work cited for "Hope Going Forward with Hop Latent Viroid (HLVd)" can be viewed at... docs.google.com/document/d/15Ecxc8ekerW7hVW0p4aTh7hoAZVGm8Nl/edit?usp=drive_link&ouid=104237452697237972847&rtpof=true&sd=true
Hope Going Forward with Hop Latent Viroid (HLVd)
Professor DeBacco
Is it Getting Worse?
Hard to tell, if the viroid is spreading or if the awareness is spreading resulting in more growers looking for it and finding it.
Why Should I Be Concerned?
Reduced yields
Pathogen spreading
No cure
Being Aware
Know what to look for and do not be afraid to test your plants.
(Carefully) tell others you may know if you think their plants may be showing symptoms and encourage them to get their plants tested.
“Unclean” Grower
If you have plants that test positive it is not an indication of bad practices.
Valuing Testing
Seed testing
Clone testing
Asking for screening reports
Finding Resistant Cultivars
To date, no cannabis cultivars are known to be resistant to HLVd.
However, remember this is still a new disease and more cultivators are now aware of it and will be actively seeking a possible resistant variety.
Sanitation Protocols
Being aware of workers
Limit contact with known infected plants
Know who was around an infected plant
Follow sanitation protocols with products that actually work against HLVd.
This is a Problem, but Research is on Going
Sharing of information both at Universities and also companies.
Link to Lecture Slides: drive.google.com/file/d/1RbFjirLoxOmyWcevdsIlZMmOoF9xb73x/view?usp=drive_link
*Due to the description character limit the full work cited for "Hope Going Forward with Hop Latent Viroid (HLVd)" can be viewed at... docs.google.com/document/d/15Ecxc8ekerW7hVW0p4aTh7hoAZVGm8Nl/edit?usp=drive_link&ouid=104237452697237972847&rtpof=true&sd=true


![Calculating Net Energy Change of a Reaction
Calculating Net Energy Change of a Reaction
Dr. DeBacco
How Its Calculated Using Bond Enthalpies
If you know the bond enthalpies of all bonds broken and formed:
ΔH = Σ (Bond energies of bonds broken) − Σ (Bond energies of bonds formed)
In other words:
Breaking bonds = energy absorbed/input (endothermic)
Forming bonds = energy released/output (exothermic)
Higher bond energy = stronger bond
So the heat of reaction tells you the net energy flow for the whole process.
Net Energy Change
To calculate the net energy change of a chemical reaction, you are essentially figuring out how much energy is absorbed or released when bonds are broken and formed.
Formula for Net Energy Change (ΔH)
ΔH = Σ(Bond energies of bonds broken) − Σ(Bond energies of bonds formed)
Breaking bonds → requires energy (positive values)
Forming bonds → releases energy (negative values)
Step-by-Step Guide
Write the balanced chemical equation.
Make sure all reactants and products are accounted for.
List all bonds broken in the reactants.
Count how many of each type of bond is broken.
List all bonds formed in the products.
Count how many of each type of bond is formed.
Use average bond energies
These are typically found in tables (e.g., C–H ≈ 413 kJ/mol, O=O ≈ 495 kJ/mol).
Plug into the formula.
Add up the energy for all bonds broken and subtract the energy for all bonds formed.
Example: Combustion of Methane
CH₄ + 2O₂ → CO₂ + 2H₂O
Bonds broken:
4 × C–H (413 kJ/mol)
2 × O=O (495 kJ/mol)
Bonds formed:
2 × C=O (799 kJ/mol)
4 × O–H (463 kJ/mol)
ΔH = [4×413 + 2×495] − [2×799 + 4×463] ΔH = [1652 + 990] − [1598 + 1852] ΔH = 2642 − 3450 = −808 kJ/mol
This reaction is exothermic, releasing 808 kJ/mol of energy.
Link to Lecture Slides: https://drive.google.com/file/d/1RVZ77V5Vt6CWEoUCQJ9D9PV3Ds_sefFR/view?usp=drive_link
*Due to the description character limit the full work cited for Calculating Net Energy Change of a Reaction can be viewed at... https://docs.google.com/document/d/1o4ZSu6akSk xD_8q9gyRspC_EypGy-b/edit?usp=drive_link&ouid=104237452697237972847&rtpof=true&sd=true Calculating Net Energy Change of a Reaction](https://i.ytimg.com/vi/iHWwrt6rrWU/mqdefault.jpg)







