Plum pox

Plum pox, caused by the Plum pox virus (PPV), is one of the most devastating viral diseases affecting stone fruit species within the genus Prunus. It is classified under the genus Potyvirus and is known to cause severe economic losses in plums, apricots, peaches, and nectarines globally.

The disease manifests through various symptoms depending on the host and variety. Common signs include chlorotic rings or spots on leaves, and characteristic deformities or color rings on the fruit surface. Affected fruits often ripen prematurely, show internal browning, and have a poor texture, making them unsuitable for fresh market or processing.

The virus is primarily transmitted by several aphid species in a non-persistent or semi-persistent manner. When aphids feed on infected trees, they acquire the virus and transmit it to healthy ones during subsequent feeding sessions. Long-distance dispersal occurs predominantly through the movement of infected nursery stock, scions, and rootstocks used in propagation.

Environmental conditions that favor the proliferation of aphid populations significantly increase the risk of disease spread. Once a tree is infected, the virus systemically colonizes all tissues, and there is no known cure. Infected trees remain a permanent source of inoculum for the entire orchard until they are removed and destroyed.

Management strategies focus on prevention and containment. Key practices include planting certified virus-free nursery stock and implementing rigorous inspection programs to identify and cull infected trees early. Effective aphid control measures are necessary to limit the transmission of the virus between trees, although they rarely provide complete protection in areas with high infection pressure.