Multiple viruses of tomato inducing fruit malformation and leaf symptoms

Abstract does not appear. First page follows.

During 1938 a serious outbreak of a peculiar disease on tomato plants was prevalent in the Byron and Brentwood districts of the northern San Joaquin Valley. At Byron approximately 95 per cent of the plants were diseased in a 96-acre field, and in other fields inspected 55 per cent were infected. Near Brentwood certain fields showed a lower percentage of infected plants. The progress of the disease was followed throughout the autumn.

(Doolittle (1936), 1942)3 was the first to report that tomato plants infected with the multiple viruses of tomato mosaic or tobacco mosaic and common cucumber mosaic bore fruits, which were deeply ridged, and when small showed pointed protuberances at the blossom end. The blossoms were commonly malformed and abortive. This disease occurred in greenhouse tomatoes in Ohio and Colorado. In Ohio, the common-cucumber-virus infection was traced to aphids evidently carrying the cucumber-mosaic virus from a nearby field of muskmelons, and in Colorado it apparently originated on cucumbers in another section of the greenhouse.

This paper deals mainly with an outbreak of the virus complex of western-cucumber and ordinary-tobacco-mosaic viruses on tomatoes in the northern San Joaquin Valley. Studies were made on the distribution and symptoms of the disease, on the effects of the multiple viruses on the flowers and fruit, and on the separation of the viruses in the virus complex. Studies were made on the aphid vectors of the western-cucumber-mosaic virus, and are herein reported. Further experiments were conducted, and are reported, with the multiple virus infections of celery calico and ordinary tobacco mosaic, and of common cucumber and ordinary tobacco mosaic.

Materials and Methods

The source of western-cucumber-mosaic virus was naturally infected tomato plants obtained from fields at Byron and near Brentwood. The original source of the celery-calico virus was naturally infected celery obtained near Milpitas in the Santa Clara Valley. Common-cucumber-mosaic virus was kindly sent to me by James Johnson, University of Wisconsin.