Which of the following is an effective practice to avoid the spread of Tomato spotted wilt tospovirus?

Using virus-free plant stock is an effective practice to avoid the spread of Tomato spotted wilt tospovirus because it directly addresses the risk of introducing the pathogen into a new area. When growers use plants that are certified as free from the virus, they create a significant barrier against initial infections. This is paramount since the virus can be transmitted to healthy plants through infected plant material and vector insects, such as thrips.

Implementing this practice helps to ensure that the plants entering the growing area do not carry the virus, thus reducing the overall incidence of disease in the crop. Additionally, when combined with other practices such as monitoring and controlling vector populations, maintaining healthy crop rotations, and managing farm hygiene, using virus-free stock can provide a robust strategy for managing Tomato spotted wilt tospovirus in agricultural settings.