Antiviral effects of dihydroxypropyladenine [RS)-DHPA) and bromovinyldeoxyuridine (BVDU) on plant viruses.

Two established antiviral agents, dihydroxypropyladenine (RS)-DHPA and bromovinyldeoxyuridine (BVDU) were evaluated for their inhibitory effects on 4 plant viruses: Tobacco mosaic virus, potato virus X (PVX), eggplant mosaic virus (EMV) and a potyvirus isolated from Solanum palinacanthum (Poty-Sp). Using the leaf disc incubation test, BVDU proved virtually inactive while (RS)-DHPA efficiently inhibited EMV and Poty-Sp when applied at concentrations as low as 5 mg/l. TMV was less susceptible to the chemical while PVX could be inhibited at drug concentrations of 100 mg/l. To achieve a similar inhibitory effect in the leaf spray test, concentrations up to 250 and 500 mg/l were required. Using these tests no phytotoxicity was observed with (RS)-DHPA at any of the concentrations used.