Biological and physicochemical properties of cowpea severe mosaic comovirus isolated from soybean in the State of Parana

Soybean plants with symptoms of bud blight were growing close to cowpea wit h severe symptoms of mosaic associated with blisters in the leaves. A group of plants of both species were collected and used for etiological studies. This kind of symptom in soybeans was common in certain areas of the State of Parana, induced by tobacco streak ilarvirus. Host range, serological rea ction, particle morphology and size, protein and nucleic acid analysis, and transmission by beetles from species Cerotoma arcuata Oliv. showed that th e virus involved was cowpea severe mosaic comovirus. This is the first repo rt on the occurrence of this virus in soybean plants in the State of Parana . Results using indirect ELISA showed that in cowpea the relative virus con centration was higher in green leaf areas than in chlorotic ones. Also, vir us concentration, determined through indirect ELISA was much higher in plan ts kept at diurnal regime of 25 degrees C x 23 degrees C (12 x 12 h) than a t 30 degrees C x 28 degrees C.