Symptoms and Signs
Plants infected with the Beet curly top virus have puckered, wrinkled leaves with edges curled downward. The leaves become thick and brittle and may turn dark green. The internodes of infected plants become shortened, resulting in dwarfing and stunting of infected plants, particularly when plants are infected at an early stage of growth. These plants produce few if any pods. Plants infected at later stages of growth may senesce early, lose flowers, and produce stunted pods.
Comments on the Disease
Beet curly top virus has a wide host range that includes beans (especially blackeyes), tomatoes, peppers, sugarbeet, melons, and other crops. The virus overwinters in perennial and annual weeds (numerous, including Russian thistle and mustard) in areas such as the foothills surrounding the Central Valley of California. The virus is transmitted from these hosts by the beet leafhopper (Circulifer tenellus) as it migrates from the foothills into agricultural areas. Yield losses caused by curly top vary considerably from year to year and can be associated with high leafhopper numbers.
Currently there are no resistant varieties or effective management practices for controlling curly top in beans. The California Department of Food and Agriculture conducts an aerial and ground insecticide spray program of leafhoppers in the foothills where they overwinter, which may decrease leafhopper migration to Central Valley fields.