Indagini eziologiche ed epidemiologiche su gravi alterazioni del mais da seme in provincia di Cremona.

In 1989, maize grown for seed crop in the Po Valley, was aïfected by a syndrome of suspected viral etiology. During a survey at the beginning of September, the symptoms observed were chlorosis, chlorotic spotting with or without reddening, total reddening of leaves and complete drying of plants. Leaf and root samples from maize plants were collected in 5 localities of the Cremona Province and checked for virus presence by mechanical inoculation, aphid transmission (Rhopalosiphum padi) and serological tests (ELISA and immunosorbent electron microscopy). Barley yellow dwarf virus (BYDV) was isolated from 19 leaf samples out of 61 tested. From 4 of these, as well as from 2 root samples, 2 strains of BYDV were contemporarely isolated from the same sample. Maize dwarf mosaic virus was isolated from 3 of 61 samples, either alone or in association with one or more strains of BYDV. No obvious association was detected between symptoms obsened and the viruses isolated.