Protection methods
- During cultivation
There is currently no curative control method that can control viral infections in the field. A plant infected with the cucurbit transmitted by aphids ( yellows virus Cucurbit aphid-borne yellows virus , CABYV) will therefore remain so throughout its life.
Insecticide treatments are useful in limiting aphid populations, if these are important on the plants of the crop. They have sometimes proved to be effective in reducing epidemics Luteoviridae in arable crops (cereals, beets). Tests carried out on melon to control CABYV were inconclusive, probably due to the short cycle of this crop and the abundance of aphid vectors.
- Next crops
Certain cultural practices that apply to all viruses transmitted by aphids can limit or delay the development of CABYV epidemics:
- carefully weed the plots and their surroundings (edges of hedges, paths, approaches to shelters, etc.) in order to eliminate sources of viruses and / or vectors;
- mulch the crops with films plastic (transparent or thermal opaque) which repel aphids. This practice is mainly intended for field crops and can delay epidemics by 2 to 3 weeks, until the foliage covers the mulch, then annihilating its repellent effect for aphids.
- protect nurseries and young plants in the field with non-woven sails (Agryl P17 type) or mesh fabrics (Filbio 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. The young shoots thus discovered can then be quickly contaminated by aphids. The use of small perforated plastic caterpillars (type 500 holes / m 2 ) is also an effective means of delaying viral epidemics which does not present the constraint of uncorking at flowering, since pollinators can penetrate under the caterpillars. However, this type of cover is not perfectly 'impervious' to aphids and care must be taken to avoid the establishment of colonies of the melon aphid, A. gossypii , which under these shelters find particularly favorable conditions for their proliferation.
- manage the space well farm and avoid planting crops intended for late production near earlier crops which risk being already contaminated.
The easiest control method for producers to use is still the use of resistant varieties when they exist.
Resistance to CABYV has been demonstrated in melon and cucumber in the genetic resources of these two species, but there is currently no resistant commercial variety. However, the melon aphid transmits CABYV much less well to melon varieties with the gene Vat .
A few commercial varieties of zucchini show a very good level of resistance to CABYV.