Ecology, epidemiology

- Conservation, sources of viruses

The mosaic virus Pepino ( Pepino mosaic virus , PepMV), viruses stable and highly contagious, is able to remain in the soil, especially in the debris of leaves and roots, and in the nursery environment and infected crops, on shelter structures like ToMV and TMV. It would survive over 90 days in dried plant material. It would also persist in contaminated wet wastes. Contaminated clothing would last it for at least 14 days.

In addition to the tomato, a rather limited number of plants seem capable of preserving and multiplying it; this is the case with some Solanaceae such as pepino, Lycopersicon chilense, L. chmielewskii, L. parviflorum and L. peruvianum . In addition, several weeds could be healthy carriers: Amaranthus sp., Malva parviflora, Solanum nigrum, Sonchus oleraceus The grafted eggplants are said to harbor the virus via their rootstocks.


- Transmission, dissemination

This virus is very easily, and primarily, transmitted by contact. A simple contact from diseased plant to healthy plant, even by the wind or by workers, is enough to transmit it. This is why all activities, all cultural operations carried out in infected crops greatly influence epidemics of PepMV. In addition, the latter seems to be easily transmitted by the nutrient solution in hydroponic systems of soilless crops, especially if the latter is recycled.

Its dissemination can be ensured by contaminated plants, but also by workers during their interventions in nurseries and crops, by their tools, but also their clothes and shoes, by crates and harvest boxes

PepMV is also transmitted at a low rate by tomato seeds, as a simple contaminant. This is because the virus is not detected in the embryo and endosperm. Note that the Peruvian strain (PE) would not be transmitted by seeds. The fruits could ensure the transmission of the virus, but this has not yet been demonstrated to our knowledge.

Finally, the bumblebees used in greenhouse to pollinate tomatoes can transmit the virus during their activities in the crop, especially if they are numerous. The auxiliary Macrolophus caliginosus could also spread it. The risks of transmitting it by hand pollination are much greater than by bumblebees. Grafting is a method which strongly favors its transmission due to numerous manipulations.