Protection methods

• During cultivation

There is currently no curative control method that makes it possible to control viral infections in the field, and in particular  virus Beet pseudo-yellow virus , BPYV); a sick plant will remain so all its life. Symptoms do not appear until after an incubation period of three to four weeks, during which time the plant can be a source of virus for whiteflies. Therefore, the purification of plants showing symptoms seems illusory to limit the spread of the disease.

On the other hand, insecticide treatments or biological control using Encarsia formosa can reduce whitefly populations if they are important, and thus slow the development of BPYV epidemics, because the vectors seem inefficient. In this case, a reduction in the populations of the latter leads to a slowing down of the rate of development of the disease.

• Next crops

There are currently no varieties resistant or tolerant to BPYV. It will therefore be necessary to have recourse to certain prophylactic measures and cultural practices likely to limit or delay the development of epidemics:
- weed carefully the plots and their surroundings (near shelters, etc.) in order to eliminate sources of virus;
- protect nurseries and young plants with non-woven sails (Agryl P17 type). Unfortunately, this type of protection must be removed, at least partially, at flowering, so as not to prevent the action of pollinating insects essential for fruit production;
- ensure good insecticide coverage at the start of the crop to limit whitefly populations in greenhouses;
- make the shelters more “airtight” against whiteflies by installing fine mesh nets on the openings;
- destroy the plants at the end of production as quickly as possible. These can be infected and it is often on them that large populations of whiteflies are established;
- manage the farm space well and avoid planting crops intended for late production near earlier crops which risk being already contaminated.