A sap-transmissible virus isolated from infected asparagus bean (Vigna sesquipedalis) in Thailand and Malaysia had a relatively wide host range, but the plants showing systemic symptoms were limited to Leguminosae. In asparagus bean juice, infectivity was lost by heating at 55-65°C for 10 minutes, by diluting to 10^-4-10^-5, and by aging at 20°C for 1-3 days. The virus consisted of flexuous filaments about 750 nm in length, and was transmitted by aphids in a non-persistent manner. The isolate from Thailand was seed-borne in cowpea but not in asparagus bean. In double-diffusion tests in agar gel plates containing lithium 3,5-diiodosalicylate, the virus reacted strongly with antiserum to the Florida isolate of blackeye cowpea mosaic virus (BlCMV) and bean common mosaic virus (BCMV). Based on these results, the virus was identified as BlCMV.