- Conservation, sources of viruses

Like the tobacco mosaic virus (TMV), the tomato ( mosaic virus Tomato mosaic virus , ToMV) is a particularly stable virus capable of persisting in soil and substrates, sometimes for several years, especially on debris. leaves and roots, as well as in the environment of nurseries and infected crops.

ToMV infects fewer species than TMV in crops. It mainly attacks nightshades such as Capsicum annuum (chili) and C. frutescens . It is less common on other species in this botanical family such as Nicotiana tabacum (tobacco), Petunia hybrida, Physalis alkekengi, P. heterophylla, P. longifolia, P. peruviana, P. subglabrata, P. virginiana, Solanum tuberosum (apple of earth), S. americanum, S. scabrum, S. villosum and, more recently, S. muricatum . It also affects some species of the following botanical families: asteraceae, chenopodiaceae, cornaceae, gentianaceae, oleaaceae, pinaceae, plantaginaceae and rosaceae.

Note that ToMV can be experimentally inoculated into at least 145 plant species, distributed in 46 genera and belonging to 27 botanical families.


- Transmission, dissemination

This virus is very easily and mainly transmitted by contact. A simple contact of a diseased plant with a healthy plant, which the wind provokes if necessary, or through the hands of the workers, their clothes and their contaminated tools, is enough to transmit it: all activities, all cultural operations carried out in infected cultures therefore greatly influence epidemics of this virus. ToMV, like TMV, would also be easily transmitted in hydroponic systems of soilless crops, via the circulating and sometimes recycled nutrient solution.

ToMV is easily transmitted by tomato seeds (external contaminations); transmission rates are sometimes considerable. The virus is in particular present in large quantities in the viscous matrix of the seeds, if it is not eliminated by fermentation or acid extraction. It is found in lesser amounts in the integuments and the albumen and does not appear to be present in the embryo. In the endosperm, the virus can be stored for up to 9 years. The young seedling is contaminated by the virus on contact with the seed coats, in particular at the time of transplanting.