Quantitative Effects of Single and Multiple Infections with Four Viruses on Tomato Production

Studying the quantitative effect of tomato viruses including tomato yellow leaf curl (TYLCV), cucumber mosaic (CMV), tomato mosaic (TMV) and potato virus Y (PVY) revealed that tomato productivity and fruit weight were severely affected by the number of viruses infected the plant at the same time. Simultaneous occurrence of the four viruses on tomato plants caused drastic reduction in the number of fruit and weight approaching 96% and 93% respectively. Also, mixed infection of tomato with three viruses reduced the number of fruit and weight by72-92% and 52-84% respectively. Plant infection with TYLCV alone reduced the fruit number by 77% and 46% for fruit weight. Single infection by either CMV or TMV caused a reduction in the number of fruit and weight by 63% and 25% or 52% and 12% respectively.