EFFECT ON CUCUMBER MOSAIC VIRUS INCIDENCE OF THE CULTIVATION OF PARTIALLY RESISTANT MUSKMELON CULTIVARS

One of the resistance mechanisms prevents the infection by CMV "Common" strains. However, some strains grouped in the "Song" pathotype are able to induce mosaic symptoms in resistant cultivars. "Song" strains are already present in the major muskmelon growing areas and a possible increase of their frequency with the use of resistant cultivars should not be underestimated.

Therefore, a study carried on over a 3 years period and during 5 successive cultures was done in order to characterize the pathotype of CMV isolates found infecting weeds growing around CMV susceptible and CMV partially resistant cultivars plots. This study leads to the following conclusions :

• the cultivation of a muskmelon cultivar which possesses the resistance to CMV "Common" strains does not induce a significant increase in the frequency of the "Song" pathotype in the vicinity of the field ;
• the percentage of weeds contaminated by CMV (all strains) is lower around the resistant cultivar field than around the susceptible one. This observation is of interest as the level of weed contamination by CMV may affect the virus epidemics in subsequent cultures as well as the number of overwintering sources.

Download Adobe Acrobat Reader (free software to read PDF files)