Soybean vein necrosis virus

Systematic position and pathogen type. The pathogen is known as Soybean vein necrosis virus (SVNV). It is classified within the Tospovirus genus of the Tospoviridae family. As a negative-sense RNA virus, it is a significant agricultural threat that primarily impacts legume production.

Diseases caused and host crops. The virus causes Soybean Vein Necrosis (SVN) disease. The primary host is soybean (Glycine max). Symptoms initially appear as vein clearing and chlorosis, which eventually progress to necrosis of the veins and surrounding tissue, leading to a mosaic-like pattern on the leaves.

Biology and life cycle. Transmission occurs primarily through thrips, specifically the soybean thrips, Neohydatothrips variabilis. The virus is acquired by larvae feeding on infected plant tissue and persists through the adult stage of the insect. Once infected, the thrips remain vectors for their entire lifespan, spreading the virus to healthy plants.

Conditions for development and spread. The spread of SVNV is highly correlated with the environmental conditions that support thrips population growth. Warm, dry weather is generally conducive to the activity of N. variabilis. Overwintering in perennial weed hosts is a critical factor for the early-season infection of emerging soybean crops.

Harmfulness and control measures. While SVN is generally not lethal to the entire plant, it causes significant physiological stress. This leads to reduced leaf area for photosynthesis, lower seed weight, and decreased total yield.

• Regular field scouting for thrips population density.
• Timely application of insecticides to manage the thrips vector.
• Sanitation practices, including weed control around fields to reduce reservoirs.
• Selecting soybean cultivars that show tolerance or resistance to viral symptoms.