Potato virus S
PVS = Potato Virus S
Causative agent and transmission
Two types of virus S strain can be distinguished: the PVS° or ordinary strain, very widespread in Europe (Germany, Poland, central Europe) and the PVSA Andean strains, classified as quarantine parasites because they produce much more severe reactions.
The virus S can be very easily transmitted both by contact, by passing machinery, for example, as well as by aphids that depend on a non-persistent mode (such as virus Y). The most frequently mentioned carrier aphids are Aphis nasturtii and Myzus persicae.
Description of symptoms on crops
(clic on photos to enlarge)
The virus S generally causes weak (latent) and variable symptoms according to the variety and viral strain:
- lightening of the foliage;
- depression of the veins on the upper side of the leaves (roughness to the touch) (photo);
- reduction in leaf size;
- tips of the leaflets inclined downwards;
- on very sensitive varieties : leaves with a bronze appearance, necrotic spots, smaller plants.
Control
The virus S has little effect on yield and the control consists of:
- Use of healthy seed potatoes;
- Testing the prebasic seed potato.
