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Cause Bean yellow mosaic virus is spread by aphids. Transmission can also occur with tools used for harvesting flowers and corms. Beans and other legumes are susceptible. The virus can overwinter in perennial legumes such as alfalfa, clovers or vetch. Almost all gladiolus cultivars are infected and should not be planted close to beans or other legume crops. Mixed infections with Cucumber mosaic virus produce more severe symptoms.
Symptoms Generally symptomless or with mild symptoms. Slight dark-to-light-green mottling of leaves, often difficult to detect, early in the summer. Flowers show a variegated white mottling. Also described as faint, inconspicuous pencil-striped break patterns that are lighter in color than the normal flower color. High temperature conditions can mask symptom expression.
Cultural control
- Use new seedling cultivars that have been tested and found to be free of all known viruses.
- Do not plant gladiolus next to beans, clover, or other legumes.
- Control aphids. See PNW Insect Management Handbook for details.
- Grow plants under fine mesh nets.
- Prevent contaminating stock plants by disinfecting cutting knives and other tools frequently. Soak tools 60 sec in 10% bleach (Clorox), or shellac thinner (70% ethyl alcohol), or quaternary ammonium (Physan 20).
- Remove and destroy symptomatic plants.
- Control weeds.
References Elmer, W.H., and Kamo, K.K. 2017. Diseases of Gladiolus. In McGovern, R.J., and Elmer, W.H. (eds.) Handbook of Florists' Crops Diseases. Springer Int.