CHICKPEA WILT INCITED BY PEA STREAK CARLAVIRUS

Pea streak carlavirus (PSV) incited a widespread wilting and yellowing disease of chickpea (Cicer arietinum) in commercial and experimental plantings in the Palouse region of eastern Washington and northern Idaho. Incidence of PSV usually ranged from 0.5 to 5%. Experimental host ranges of several Palouse PSV isolates were confined to the Fabaceae and one species of Amaranthaceae. Systemic necrosis developed in chickpea, lentil (Lens culinaris), pea (Pisum sativum), fenugreek (Trigonella foenum-graecum), and faba bean (Vicia faba), while alfalfa (Medicago sativa), white sweet clover (Melilotus alba), and hairy vetch (Vicia villosa subsp. villosa) were symptomless carriers of PSV. The virus produced local lesions without systemic spread in Gomphrena globosa, Senna obtusifolia, and S. occidentalis. At Central Ferry, Washington, the virus was isolated from naturally infected Medicago lupulina, M. sativa, and Melilotus alba, but not from 40 other wild species. Pea streak virus was isolated from 93% of alfalfa fields sampled, and virus incidence ranged from 0 to 44%, making alfalfa the primary reservoir and overwintering host of PSV in the Palouse region. All 55 cultivated chickpea germ plasm accessions tested, as well as eight wild annual species of Cicer, were susceptible to PSV in inoculation tests. Four wild perennial species of Cicer were resistant to the virus. Seed yields of three chickpea lines were reduced 97-99% by inoculation at prebloom and 16-50% by inoculation at full bloom. Seed quality was also adversely affected. No seed transmission of PSV was detected in chickpea, lentil, M. lupulina, or M. sativa. The pea aphid (Acyrthosiphon pisum) transmitted PSV in a nonpersistent manner.