Control measures

It is essential to use certified seed potatoes to limit the infection of potato crops by viral diseases, particularly PVY. Production of certified seed potato is formally based on a range of strict measures designed to limit the infection by viral diseases. They include:

• the use of certified seed tubers resulting from the multiplication of virus-free material in a certification programme (including multiplication systems such as in vitro micropropagation, intensive field inspections and large-scale post-harvest testing);

• the production in a favourable environment in isolated areas with low virus/vector pressure and in fields away from household gardens or away from fields used for the production of ware/processed potatoes;

• the early roguing of diseased plants and eradication of all sources of inoculum, e.g. weeds or volunteer potatoes to inhibit the spread of viruses within the field;

• the treatment with mineral oils to reduce the transmission of non-persistent viruses such as PVY. Insecticides are only effective against persistent viruses such as the Potato leaf roll virus;

• the use of potato cultivars with a good level of resistance to PVY may be useful in areas with favourable conditions for vectors and virus development.

Additional control measures in seed potato production taking into account risks of aphid infestations that are usually higher during warm periods, include:

• early planting to avoid the flights of aphids in summer;

• early haulm destruction (by chemicals and/or mechanical means) prior to maturity to limit the infection of daughter tubers.