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Serological Grouping of Isolates of Blackeye Cowpea Mosaic and Cowpea Aphidborne Mosaic Viruses. M. A. Taiwo, Former graduate student, Department of Plant Pathology, New York State Agricultural Experiment Station, Cornell University, Geneva 14456; D. Gonsalves, associate professor, Department of Plant Pathology, New York State Agricultural Experiment Station, Cornell University, Geneva 14456. Phytopathology 72:583-589. Accepted for publication 18 August 1981. Copyright 1982 The American Phytopathological Society. DOI: 10.1094/Phyto-72-583.

Antisera were prepared to two single-lesion isolates of blackeye cowpea mosaic virus (BICMV), one each from Florida and New York, and four single-lesion isolates of cowpea aphidborne mosaic virus (CAMV), one each from Cyprus, Kenya, Morocco, and Nigeria. Enzyme-linked immunosorbent assay (ELISA), immune electron microscopy (IEM), and immunodiffusion in sodium dodecyl sulfate (SDS) were used to compare these isolates. Results indicated two serological groups, which we defined as BICMV and CAMV. The BICMV group was comprised of both isolates of BICMV and the Kenya and Nigeria isolates of CAMV. The CAMV group contained the Morocco and Cyprus isolates. In all tests, isolates within a group showed very close, if not identical, serological relationship. Antisera to isolates of the CAMV group did not detectably react to isolates of the BICMV group. Similarly, antisera to the Florida and Nigeria isolates did not react with members of our CAMV group in SDS-immunodiffusion and ELISA. However, antisera from bleedings taken 16 wk or more after injecting rabbits with the New York and Kenya isolates reacted weakly with Morocco and Cyprus isolates in SDS-immunodiffusion tests. Antisera to all isolates in our BICMV group moderately decorated the isolates in our CAMV group, but no decoration was observed in the reciprocal test. In reciprocal SDS-immunodiffusion tests, antisera to isolates in our BICMV group reacted strongly with bean common mosaic virus (BCMV) with slight spurs, whereas BCMV antiserum gave reactions of homology to all four antigens. No reaction to BCMV was detected in SDS-immunodiffusion tests when antisera to isolates in the CAMV group was used. BCMV antiserum, however, gave a weak reaction to CAMV isolates in reciprocal tests.