Common Plant Diseases that Affect Cannabis Propagation

Cannabis has been used for many years as a medicine, food, and textile fiber. This plant is most well-known for its medicinal properties and ability to treat conditions like epilepsy, fatigue and glaucoma. Multiple sclerosis and HIV/AIDS have been treated with some of its derivatives.Cannabis sativa, also known as marijuana or hemp, is a member of the Cannabaceae family. There are many secondary metabolites in cannabis that can be used for medical purposes. The major cannabinoids in the plant include CBD, THCV and CBC.It has become a rapidly growing market for its many applications. However, large-scale cultivation poses a problem due to the possibility of microbial and pest infections, transport challenges and uniformity among the cannabis crops.This article focuses on the microbes that pose a serious threat in vitro as well as ex vitro.Many microorganisms can infect cannabis, including bacteria and viruses. Of all the microbes/organisms mentioned, fungi is the most common. Then there are viroids, viruses and others that can infect cannabis. The diseases are also categorized based on the tissue they infect, which include root and crown infecting, foliar and stem-infecting, inflorescence-infecting, and postharvest pathogens. Farmers and culturists are affected by these diseases and lose time, money, effort, and even their time.

Bacterial Diseases

Some bacteria causing infecting Cannabis plants include Pseudomonas syringae and Xanthomonas campestris pv. Cannabis. Pseudomonas Syringae is a condition in which small, water-soaked leaf spots may appear. These veins can then enlarge and turn brown. Leaf spots and wilting can be caused by the Xanthomonas Campestris.

Fungal Diseases

These are some of the most serious cannabis-related diseases and infecting fungus.

• Fusarium oxysporum f.sp. Wilt is a condition caused by cannabis. It causes yellowing of the leaves, poor growth and wilting.
• Pythium is a root rot or damping-off condition that causes root rot. The symptoms include small roots lesions and severe root damage. Young seedlings are also affected by damping-off.
• Sclerotinia succumbiorum can cause hemp canker. The initial symptoms are water-soaked lesions on the stalks and branches. These can then lead to cankers. Sometimes, sclerotia and cottony white mycelium may also be present.
• Powdery mildew can be caused by Sphaeorotheca magna or Leveillula taurica It is one of the most prevalent foliar conditions of cannabis. It causes a powdery growth on leaves that eventually turns brown.
• Alternaria species can also affect cannabis plants, causing brown blight and leaf spot.

Viral and Viroid Diseases

Hop mosaic virus, ApMV, Hop stunt viroid (HSVd), Hop virus (ApMV), Hop mosaic virus in Hop (ArMV), Alfalfa virus in Hop (AMV), Hop mosaic virus in Hop (TMC), Hop mosaic virus and Cucumber mosaic viruses (CMV) are all viruses that can affect cannabis.Viral infections can lead to severe crop damage, reduced growth, and even decreased yields. Common symptoms include curling, distortion and narrowing of young cannabis leaves, as well as yellow and green mosaic patterns. Phytoplasmas are responsible for severe shoot proliferation and stunted development.Hop latent viruses (HLVd) have been shown to be most prevalent in California, Canada, and other parts of the USA. The symptoms of this disease include brittle stems and stretched or horizontal plant growth, stunting, malformed leaves or leaves, and small, malformed flowers.Infected plants can spread the virus and infect other plants by cuttings and possibly seeds, mother plants and cuttings. HpLVD can also be spread through infected tools, equipment, hands and clothing.

• The identification of fungi and oomycetes can be first done at the genus level by identifying the morphological characteristics/features. The next step is species identification by molecular methods. These include polymerase chain reactions (PCR) of ribosomal DNA regions that contain the intergeneric and internal transcribed spacesrs (ITS).
• PCR methods that use the 16S region in ribosomal RNA can identify bacteria pathogens.
• Viroids and viruses can be identified using molecular analysis, which involves RT-PCR and next-generation sequencing (NGS).

The prevention of cannabis diseases, including the introduction of inoculum, infection, or symptom development, can help to control them. It also helps to reduce secondary inoculum production, spread, and survival of the pathogen. Here are some ways to prevent cannabis diseases.

• In cannabis-growing areas, ensure cleanliness and sanitation.
• Air purifiers such as HEPA filters or UV can be used to reduce the airborne pathogens and contaminants.
• Clean and sanitize all equipment, tools, dehumidifiers and air filters.
• Botrytis can be minimized by maintaining a comfortable humidity level, a higher temperature, better circulation, and dry, clean areas.
• Treatment of irrigation water with UV, chlorine or other registered products can prevent root rot, crown and stem rot, as well as damping-off.
• Use disease-free stock, or cuttings of healthy mother plants, for the cultivation process. You must inspect and quarantine all plant material before it enters the facility.
• Hop Latent Viroids can be eliminated by ensuring that your stock plants are healthy and removing or destroying infected plants.

Prevention of Diseases in Cannabis Plants:To prevent diseases in your cannabis plants, you can opt for the following methods:

• Micropropagation
• Meristem Dissection
• Pathogen Remediation

Many companies offer Cannabis Tissue Culture services that will help you optimize your cultivation operations through the provision of data-proven, proprietary SOPs and protocols.