Common And Yellow Mosaics
Bean common mosaic virus and Bean yellow mosaic virus
3 host plants
Last updated
This profile contains verified disease data from extension databases. Regional field notes and expert review are in progress.
Virus mosaics cause mottled, variegated leaf patterns in yellows and greens on certain legume plants and relatives. Infected leaves may be smaller than normal and distorted, and affected plants show reduced vigor and delayed growth. The viruses spread readily through aphid vectors, particularly in spring when young growth is most susceptible. Virus-infected plants remain infected for life and are a continuous source of virus for spreading to nearby healthy plants.
Since no cure exists, prevention is your only strategy: choose resistant varieties when available, and keep virus-carrying plants like clover and gladiolus away from susceptible crops. Scout regularly for aphids and manage populations if they appear, though controlling aphids completely is difficult. Remove infected plants promptly to reduce virus sources in your garden. The most reliable path is to plant resistant cultivars from the start; resistant bean varieties like Oregon 54 and Roma II are available and perform well in the region.
Quick Reference
Management
Highest risk during seedling to early flowering stages (4-8 weeks after planting) when young plants are most susceptible to aphid-transmitted infection. Spring and early summer (May-July) correspond to peak aphid activity in PNW. Plants infected early show most severe stunting and yield loss. Seed production crops are vulnerable during flowering and pod-fill when virus can be incorporated into developing seed. Perennial reservoirs (clover, gladioli, other hosts) maintain virus through winter. Source: PNW Plant Disease Management Handbook
Warm growing-season temperatures (18-25°C) favor aphid activity and virus multiplication. High aphid populations increase disease incidence. Susceptible bean varieties are most severely affected. Young seedling stage plants are highly vulnerable to infection. Seed-borne virus in infected seed germinates with primary infection already present. Stress from other factors may increase symptom severity in systemically infected plants. Source: PNW Plant Disease Management Handbook
Cultural Controls
- Avoid planting beans near clover or gladioli, which may carry the Bean Yellow Mosaic Virus.
- The varieties 'BB 110', 'Goldrush', 'Oregon 54', 'Oregon 91G', and 'Roma II' are reported to be resistant to Bean Common Mosaic Virus strains.
- For more information on virus-resistant bean varieties, see the current PNW Plant Disease Management Handbook.
- Controlling aphids may be of some help in preventing spread of the viruses.