Plant bunyaviruses

Bunyaviricetes is a major viral class, with the order Bunyavirales containing the family Tospoviridae, which are economically damaging plant pathogens. These viruses possess a segmented negative-sense RNA genome and are known for their complex interaction with both the plant host and their insect vectors. They represent a global challenge for sustainable food production.

The host range of these viruses is remarkably broad, affecting numerous commercial crops such as tomatoes, bell peppers, tobacco, lettuce, and many ornamental species. Due to their ability to colonize various tissues, they can disrupt physiological processes, leading to reduced photosynthesis and impaired reproductive development in infected plants.

Visible symptoms often present as mosaic patterns, chlorotic or necrotic rings, stunting, and fruit malformation. In many cases, the fruit of infected plants exhibits distinctive concentric rings or blotchy ripening, which renders the produce commercially unmarketable. The severity of symptoms depends on the plant species and the timing of the initial infection.

Transmission occurs primarily through the feeding activity of thrips (Thysanoptera). Once a thrips larva acquires the virus, it remains a vector for the rest of its life cycle, facilitating the rapid spread of the pathogen within greenhouses and across field crops. Environmental conditions, especially temperature and humidity, play a critical role in the reproduction rate of these insect vectors.

Effective management requires an integrated pest management (IPM) strategy. Key practices include the cultivation of resistant plant varieties, rigorous weed management to remove alternative hosts, and the application of biological and chemical controls against thrips populations. Additionally, implementing sanitation protocols for tools and greenhouse structures is essential to prevent secondary transmission.