Zucchini yellow mosaic virus (ZYMV)

Zucchini yellow mosaic virus

General

• Potyvirus transmitted by different species of aphids in the non-persistent mode.
• Reported on all continents and in all climates, regularly encountered on Cucurbitaceae cultivated in tropical and subtropical regions.
• Its early attacks and very spectacular symptoms can lead to significant crop losses.
• Many strains causing quite different symptoms on Cucurbitaceae.
• Virus rather specialized in Cucurbitaceae.
• Observed mainly in the open field, sometimes under shelter.

• Susceptible botanical family(s)

• Production areas affected :

• Organs attacked

Symptoms

• Symptoms :
  • Vein clearing, yellowing, slightly distorted mosaic with vein banding (figures 1 to 3-zucchini; 6 to 8-cucumber; figure 14-melon)
  • Deformation with new leaves that are very deformed: puffiness, dark green blisters (figures 11 to 13), filiformia, enations*.
  • Stalled growth, very short internodes, blocked plants with a bushy or erect habit.
  • Very rapid wilting of the infected plant.
  • Mosaics, blisters (figures 4 and 5-zucchini; 9 and 10-cucumber; 15-melon), bursting on fruits (figure 16), with sometimes deformation of the seeds. The flesh may be discolored and remain tough.
• Possible confusion : CMV, WMV
• Signs : no visible signs, confirm the possible presence of aphids.

* An enation is a leaf deformation leading to the appearance of small cupules on the upper or lower face of the leaf blade.

Biology 

• Conservation : is maintained in sub-tropical or tropical zones on wild cucurbits (virus reservoir) but also on those which can be cultivated all year round, the virus passing from one culture to another thanks to the aphid vectors.

• Transmission : according to the non-persistent mode by more than 11 species of aphids (the aphid-vector is able to acquire the virus or to transmit it during very brief bites, of the order of a few tens of seconds) ( Aphis gossypii , Myzus persicae , etc.). Transmission by contact during harvesting or pruning operations suspected from time to time. Does not appear to be seedborne in cucumber or melon, possible in squash.

Protection 

• Use resistant varieties (cucumber, zucchini).
• Protect nurseries and young plants in the field with veils (Agryl P17 type) or mesh fabrics (Filbio type).
• Avoid setting up a new culture near old cultures that may already be contaminated
• Carefully weed the plots and their surroundings in order to eliminate sources of viruses and/or vectors.
• Mulch crops with  plastic film to keep aphids away
• Eliminate the first infected plants .
• Chemical vector control is not effective in controlling this virus.