Feasibility of Cross-Protection for Control of Tomato Mosaic Virus in Fresh Market Field-Grown Tomatoes. Ali Ahoonmanesh, Department of Plant Pathology, University of California, Davis 95616. T. A. Shalla, Department of Plant Pathology, University of California, Davis 95616. Plant Dis. 65:56-58. Copyright 1981 American Phytopathological Society. DOI: 10.1094/PD-65-56.

The feasibility of using cross-protection for control of tomato mosaic virus (TMV) in fresh market tomatoes was tested in field plots with random and Latin-square designs. Tomato seedlings (Lycopersicon esculentum Mill. ‘Ace 55’ and ‘7718’) were inoculated in the cotyledon stage with a mild strain of TMV isolated from commercially grown tomatoes in California and with the MII-16 mutant. Sixteen days later they were reinoculated (challenged) with a severe strain of TMV also isolated from California-grown tomatoes. Cross-protected plants were nearly equal in fruit yield and quality to those inoculated only with the mild strain and to buffer-inoculated controls. The yield of cross-protected plants was 50% higher and there was 10% more extra-large fruit than on plants inoculated only with the severe strain. The effectiveness of protection did not differ between the naturally occurring M strain and the artificial mutant MII-16.