Which agricultural practice helps combat the spread of Tobacco/Tomato mosaic tobamovirus?

Using disease-free seed is a fundamental agricultural practice to combat the spread of Tobacco/Tomato mosaic tobamovirus, a pathogen that can severely affect crops like tomatoes and tobacco. The virus can be present in infected seeds and, once those seeds are planted, can lead to increased rates of infection in the resulting plants. By ensuring that only seeds free from the virus are used, farmers can significantly reduce the incidence of the disease in their crops, therefore preventing the virus from spreading within fields and to adjacent plants.

In contrast, while practices like fertilizer application and heavy irrigation may support plant growth, they do not address the presence or transmission of the virus itself. Similarly, crop densification involves planting crops closer together, which can actually facilitate the spread of pathogens due to increased humidity and reduced air circulation, making it a less effective strategy against viruses like the tobamovirus. By emphasizing the use of disease-free seed, growers can better manage and mitigate the risks associated with this pervasive virus.