CROSS-PROTECTION AS A CONTROL STRATEGY FOR PEPINO MOSAIC VIRUS (PEPMV) IN GREENHOUSE TOMATO

Abstract

Pepino mosaic virus (PepMV) is a highly infectious Potexvirus, which has been observed for the first time in tomato crops in The Netherlands about a decade ago and has presently become a major disease of tomato crops worldwide. Control measures consist of strict hygienic measures to prevent infection, albeit these measures often fail, especially in dense tomato production areas. However, previous studies indicate that cross-protection can be effective. The potential of three mild PepMV isolates, belonging to the CH2, EU and LP genotypes, to protect a tomato crop against an aggressive challenge isolate of the CH2 genotype was assessed in a summer crop in plastic tunnels. Enhanced symptom display was observed in plants that were pre-inoculated with a protector isolate belonging to a different genotype (EU, LP) as the challenge isolate (CH2), while effective cross-protection was obtained using the mild CH2 isolate. As the PepMV population in Belgium and neighbouring countries is dominated by the CH2 genotype, cross-protection using this mild CH2 isolate could be an effective strategy for controlling PepMV. Therefore, in this study we further assess the potential of this vaccination strategy. The efficiency of the mild CH2 isolate to protect a crop from another aggressive, mutant CH2 variant (CH2-pvu), which is currently spreading in the area, was assessed in a summer crop in plastic tunnels. In addition glasshouse trials in conditions similar to commercial tomato production are currently being carried out, in which the response of a wide range of tomato varieties to the mild CH2 isolate is studied, next to the cross-protection efficiency under two different climate strategies.