Tomato Bushy Stunt Virus (TBSV) is a soil- and waterborne virus, first identified in the 1930s (Smith 1935). This virus primarily infects plants in the Solanaceae family, including tomato, pepper and eggplant, causing symptoms such as lesions and necrotic spots, which in severe cases, can kill the plant. TBSV symptoms vary species to species, and may include necrotic and chlorotic lesions, mosaicism, and in severe cases, plant death (Yamamura and Scholthof, 2005). Together, these symptoms can stunt the growth of the plant and increase lateral shoots, giving the plant a bushy appearance and the virus its name.
Since its discovery, TBSV has become a model for studying the nature of plant-virus interactions, and these experiments have shown it can infect a much wider spectrum of plants under laboratory conditions (Yamamura and Scholthof, 2005). Some infected plants species show symptoms of the virus, while in others the infection remains localized to one area or tissue. TBSV is one of a handful of viruses and viroids that have been identified in cannabis, but due to the limited number of cannabis pathology studies completed to date, it is not clear whether TBSV forms local or systemic infection in cannabis, nor is it clear how severe the infection may be.
While TBSV is not considered to be of high economically importance in cannabis, infection can potentially result in stunted growth and diminished yield. Standard best practices for limiting the spread of any virus or viroid apply to TBSV, such as regularly cleaning and sanitizing of the grow environment and using clean tools and equipment. As a soil- and waterborne virus, it is particularly important to design your water circulation system in a way that mitigates spread. This may include ensuring adequate drainage of water and ensuring that runoff does not contact growth substrate of adjacent plants. Finally, as TBSV can spread in water, it may be more of a risk to hydroponic grow facilities. In this case, installation of a water sterilization system that is effective against viruses (such as UV or Ozone) is essential to keep water free of TBSV and other pathogens.
In conclusion, being a soil- and water-borne virus means that TBSV can spread quickly throughout a facility. It is therefore important to have proper preventative measures in place, to ensure that water sources are clean and infected runoff is not recirculated to healthy plants. While it is not known how severe TBSV infections are in cannabis, comparative studies from other plants show that large reductions in yield can result. As such it important to screen plants for this virus and act proactively to prevent its spread.
Smith KM (1935) A new virus disease of the tomato. Ann. Appl. Biol., 22:731-741.
Yamamura Y, Scholthof HB (2005) Tomato bushy stunt virus: a resilient model system to study virus–plant interactions. Mol. Plant. Pathol., 6:491-502.