Growers around the world in grow facilities have all been in the situation of their crops all growing beautifully, but sprinkled through the crops are the small ‘non thriver’ plants. The ones that many call duds. This was once a mystery and attributed to a mutation or poor genetics. However, recent studies have discovered that these non-thriver plants may be victims of a harmful viroid that crossed over from hops. Although in its original species, Hop Latent Viroid doesn’t have much effect or symptoms, in hemp and other hemp related crops, it causes some serious damage.
Hemp Latent Viroid- What is it?
Hemp latent viroid is also known as HLV in the industry. This viroid had its start in hop crops and was very recently discovered in hemp crops. This viroid was named Humulus lupulus and was found in the United States and other areas of the world such as New Zealand, the UK, Brazil, Japan, and other areas. The Dark Heart Nursery had indicated that it was detected in California as early as 2017. 90 percent of California facilities tested at the time were positive for the pathogen. This higher percentage of infected plants had an estimated possible loss value of around $4 billion USD. In addition, this viroid may be linked to a medical condition known as hyperemesis syndrome or CHS.
How does HLV Impact Plants?
Hop latent viroid is a pressing issue in the hop and hemp industries and can be known as dudding or stunting. In hops, as previously mentioned, it does not exhibit symptoms, but in hemp it shows moderate to severe impacts in yield, trichome and leaf counts, and other characteristics such as bud size and count. This is so heavily prevalent in growing operations that growers are referring to it as Covid-420. Why should growers be so concerned with this RNA viroid?
This is a silent viroid that stealthily moves through a growing operation before being noticed in the early stages. This is in part because the early symptoms can be attributed to more common growing issues such as chlorosis or yellowing leaves, brittle stems, slower growth, small leaves, and other growth related issues. Branching can also be affected with either odd branching patterns or outward growth. Many of the early signs can be attributed to environmental or nutritional deficiencies. It is in the late stages of the viroid’s attack that it can be recognized as HLV.
Late stage symptoms and signs of infection include the reduction of trichomes, dull smell, smaller buds, and either no terpenes or a greatly reduced terpenes count. The most startling is the overall reduction of size and growth with data showing an up to 50 percent reduction of hemp production. With the late stages being so evident and noticeable, this is typically the time growers take notice. However, this viroid is highly infectious and may have infected the entire growing area by the time something is noticed by the untrained eye. If there are any doubts of an infection in an operation, everything needs to be treated as if it IS infected.
Areas of HLV transmission
- Infected equipment
- Clones
- Seeds
- Human touch
- Pests
How can HLV Be Prevented or Removed?
By keeping good practices in the grow operation, disease and other issues in the operation can be greatly reduced. HLV is spread mostly through infected equipment and the use of infected plant material such as mother plants and seeds. An excellent way to help reduce the spread of HLV is to sterilize all equipment and housing areas during the season and after. Before creating clones, a grower should perform a pathogen test on mother plants to run a pathogen panel to detect HLV and other pathogens that could be passed through the clones. Seeds have a very low transmission rate of HLV, but there is a small chance of spread. Always purchase seeds from trusted suppliers to ensure quality. Human touch is another huge transmitter of HLV to plants. Cultivation managers and employees should always sanitize their hands and nitrile gloves before moving from plant to plant. A simple touch is enough to transmit HLV. For pests and insects, bites can transmit HLV to other plants. So an Integrated Pest Management program is essential in the control of pests in the operation to reduce possible transmission rates.
It should be noted that all plants found with stunted or dudded growth should be pathogen tested before removal in order to ensure that HLV is not the cause. Removal of infected plants and doing a hard restart of crops is needed to remove the viroid from the production line.
For more information:
RF Agriculture
622 North La Brea Avenue
Inglewood, CA 90302
T: (310) 967-2022
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rfagriculture.com