Cucumber mosaic virus (CMV) 

General

• Cucumovirus transmitted by different species of aphids in the non-persistent mode.
• Reported on all continents and in all climates.
• Extremely polyphagous virus, more than 1000 plant species are affected, and in particular many market garden species (tomato, pepper, lettuce, spinach), fruit tree (cherry tree, banana tree) and weeds. Rather rare on eggplant.
• Serious attacks are reported in Italy, Israel, India, etc.
• Organs attacked  : leaves, fruits, stems.
• Symptoms :
  
  • Marbling, mosaic more or less visible on leaves. Annular motifs, in chlorotic arabesques on the blade.
  • Nerve necrosis followed by deformation of the limbus.
  • Fruits small, deformed, showing concentric necrotic rings, chlorotic streaks.
  • Reduced plant growth, fertility and size of already developing fruits. Stunted, even bushy appearance of plants.
• >>> More pictures
• Signs : no visible sign, confirm the possible presence of aphids.
• Possible confusion :

Biology

• Conservation : perennialize on many cultivated plants and weeds present in the environment of crops, considered as virus reservoir plants. Note that these plants also harbor vector aphids ( Aphis  gossypii,  Myzus persicae , Aphis fabae , Aphis craccivora, etc.)

• Transmission : according to the non-persistent mode by more than sixty species of aphids (the aphid-vector is capable of acquiring the virus or of transmitting it during very brief bites, of the order of a few tens of seconds ). Does not appear to be seed-borne in cucumber or melon, possible in squash and some weeds.

Protection

• Protect nurseries and young plants in the field with non-woven sails (Agryl P17 type) or mesh fabrics (Filbio type).
• Avoid setting up a new crop near old crops 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 films  plastic to keep aphids away
• Eliminate the first infected plants.
• Chemical control of vectors is not very effective in controlling this virus.