OZONE RESPONSE OF TOMATO PLANTS INFECTED WITH CUCUMBER MOSAIC VIRUS AND/OR TOBACCO MOSAIC VIRUS

The sensitivity of three tomato cultivars to several concentrations of ozone was evaluated after prior sequential inoculations with tobacco mosaic virus (TMV) and/or cucumber mosaic virus (CMV). Ozone injury in inoculated and uninoculated tomatoes varied from slight to severe depending on the virus, cultivar, ozone concentration and virus incubation period. The frequency of increased ozone injury was about twice as great as that of suppressed injury on infected plants. Ozone injury occurred more frequently in TMV-inoculated plants than in those inoculated with CMV. There were more increases than decreases in ozone injury after 7 or 14 days of virus infection, but mainly decreases in injury after 21 days infection. Growth was significantly reduced in plants exposed to ozone after a 21-day virus incubation period, particularly when they were inoculated with both viruses.