Soybean Mosaic
Symptoms:
- Soybean mosaic causes stunting of plants and crinkled and mottling of leaves.
- Infected plants range from no symptoms to severely mottled and deformed.
- The leaf blades are puckered along the veins and curled downward.
- The mottling appears as light and dark green patches on individual leaves.
- Symptoms can be difficult to see when temperatures are above 90°F.
- Do not confuse with growth regulator herbicide damage where the leaves will be elongated and which usually occurs in a pattern such as along a field edge.
- Soybean mosaic can also reduce seed size and pod number per plant, and soybean mosaic is one of several factors associated with discoloration of seeds, causing a dark discolored tear stain origination at the hilum.
- The virus can interact with bean pod mottle virus (BPMV) to create severe symptoms in plants infected with both viruses.
Pathogen Involved:
- Soybean mosaic virus (SMV). This virus has a wide host range including pea and snap bean.
- SMV is transmitted by aphids and infected seed.
Time of Occurrence:
- All season.
Conditions Favoring Disease:
- Plants infected when young tend to show more symptoms than plants that infected when older.
- Higher activity or populations of aphids favor virus transmission.
Disease Management:
- Plant seeds free of SMV.
- Plant early.