Ecology, epidemiology

• Conservation

The virus des taches en anneaux du papayer ( Papaya ringspot virus , PRSV), et en particulier les souches PRSV-W, n infecte pratiquement que des espèces owned aux cucurbitacées . However, it does not attack the two species of spontaneous Cucurbitaceae found in France ( bryone and Ecballium elaterium ) which therefore cannot be reservoirs of the virus between two cultures. As a result, PRSV can only be maintained in areas where Cucurbitaceae is grown all year round (Nice region) or in areas (such as the West Indies) where wild Cucurbitaceae are found. sensitive ( Cucumis anguria , Cucurbita sp., Momordica sp .). It is also possible that this virus could be introduced into France from more southern countries, either by stealing aphids or by importing contaminated fruit.

• Transmission

PRSV is transmitted non-persistent by more than 24 aphid species , including the melon aphid ( Aphis gossypii ), the green peach ( aphid Myzus persicae ), as well as A. crassivora and Macrosiphum euphorbiae . The vector is capable of acquiring the virus on an infected plant, or of transmitting it to a healthy plant, during very brief bites of the order of a few tens of seconds ("test" bites allowing the insect to recognize if the plant on which it has landed is a favorable host for its development). The aphid remains able to transmit the disease generally for a few tens of minutes to a few hours, but it quickly loses this ability if it makes several successive test bites or feeding bites in the phloem. The very high efficiency of this mode of transmission means that the disease can spread in a crop without significant outbreaks of aphids having been observed.

PRSV has not been reported to be seed-borne in melon, cucumber or zucchini.

In the laboratory, this virus is easily transmitted mechanically, but this mode of plant-to-plant transmission does not appear to occur in the field and play a significant role in the spread of the virus under natural conditions.