Prunus necrotic ringspot virus

Prunus necrotic ringspot virus (PNRSV) is a widespread plant pathogen belonging to the Ilarvirus genus. As a systemic viral infection, it colonizes the vascular system of the host plant, disrupting physiological processes and significantly weakening the overall health of stone fruit trees over several seasons.

The virus primarily affects species within the Prunus genus, including cherry, sweet cherry, peach, plum, apricot, and almond. Secondary hosts, which can serve as environmental reservoirs, include roses, hops, and various ornamental shrubs commonly found in proximity to commercial orchards.

Symptoms are most visible during the early spring and include chlorotic or necrotic rings, patterns, and spots on the leaves. In more severe cases, leaves become deformed or tattered. The impact on production is substantial, manifesting as reduced fruit size, diminished yields, and an overall lack of vigor that leaves the trees susceptible to secondary pests.

Transmission occurs through vegetative propagation, such as infected rootstocks or scion wood. Additionally, the virus spreads through pollen, which can infect healthy trees during pollination. Mechanical transmission via contaminated pruning equipment is also a major factor if tools are not sterilized between trees.

Effective management strategies center on prevention, as there is no chemical cure for systemic viral infections. Key measures include:

• Procuring certified virus-free planting stock.
• Rigorous sanitation and disinfection of pruning tools using appropriate virucidal agents.
• Removal and destruction of symptomatic trees to limit the inoculum source.
• Maintaining healthy orchard environments to minimize stress and secondary infections.