Testing single ToBRFV infection and ToBRFV in combination with PepMV

Pepino Mosaic Virus (PepMV) is present in many tomato-growing countries. This creates the possibility that tomatoes can be infected by PepMV, ToBRFV, or a combination of both. 

There are potentially many combinations of infection, be it ToBRFV – PepMV or vice versa or even tri-infection with TYLCV. Through our observations and technical discussion with our customers, Vegetables by Bayer is evaluating new tomato varieties in two ways that best reflect the real life and common practices of growers: with only a single ToBRFV infection and with a controlled infection of PepMV* followed by ToBRFV infection, here described as co-infection.

*PepMV is introduced via vaccination

In these trials, ToBRFV inoculation is carried out at an early stage, some weeks after planting. Our experience is that young plants are very susceptible to ToBRFV, with the virus multiplying fast and producing visible but not extreme symptoms. There do not appear to be differences in the symptoms caused by a single ToBRFV infection or by ToBRFV infection after vaccination with PepMV. Brown spots and rings are most likely from ToBRFV.

This suggests that young plants are actively growing very quickly, so the virus also increases and reaches high levels very quickly.

No silver bullet to mitigate ToBRFV co-infection

Co-infection with aggressive viruses is a big challenge, as any uncontrolled infections will reduce yields. Growers will need to adopt and maintain a high level of hygiene practices to maximize the number of productive plants and minimize ToBRFV infections at the end of the crop cycle.