Cause Beet curly top virus (BCTV) is spread by the beet leafhopper. Other crop hosts include sugar beet, watermelon, tomato, annual flowers, and cucurbit. The disease is cyclic but occurs frequently in the Columbia Basin, southern Idaho, and central Oregon. The virus overwinters in wild perennial or winter annual hosts and is not seedborne.
Symptoms Symptoms range widely depending on varietal sensitivity, growth stage of host, temperature, and virus strain. The predominant symptom is stunting. On young plants, the trifoliolate leaves pucker and curl down. General yellowing and death follow. Older affected plants become yellowed, dwarfed, and bunchy, and pods are stunted. Beet curly top symptoms of leaf curling and chlorosis may be confused with similar symptoms caused by bean yellow mosaic virus (BYMV) infection. However, leaf curling and cupping due to BCTV infection generally affect younger leaves more severely; BYMV more severely affects older leaves are. All leaves become thicker than normal and, being very brittle, break off easily at the stem. Infected plants yield few or no pods.
Cultural control Use resistant varieties. In general, varieties in the pinto, pink, and small-red market classes are resistant. Navy, black, and great Northern varieties range from moderately resistant to moderately susceptible.
Resistant snap bean varieties include Canyon, Yakima, Idaho Bountiful, Idachief, Idelite, and Wondergreen.
Resistant red kidney varieties include Kamaikin and Kardinal Light. Two resistant cranberry varieties are Cardinal and UI 50.
Consult specific varieties descriptions to be certain of their disease reaction.