The foremost control measure of Plum pox virus (PPV) is exclusion. Commercial growers and nursery propagators should only purchase planting stock that is certified virus-tested after it has been assayed for PPV and other viruses. A careful selection and limited exchange of budwood to avoid dissemination of virus-infected materials is critical in avoiding human transmission of the disease. Also, the production of PPV-free trees through the selection of PPV-free budwood and rootstocks is vital to preventing virus spread to new orchards and regions.
The timely elimination of any infected trees is a critically important control method for PPV. There is no treatment for PPV, nor is there any cure in infected orchards; once a tree has been confirmed to have PPV it should be removed as quickly as possible to limit spread of the virus to neighboring trees. If tree stumps are left behind they should be treated with a systemic herbicide to avoid the development of sucker shoots, which can also carry PPV.
Chemical control of aphids is not a feasible management tool of PPV; application of insecticides may reduce the overall population of aphid vectors over a growing season, but a single aphid can transmit PPV to a new host in a matter of seconds. Furthermore, total control of aphid vectors is impossible to achieve.
Plant resistance is the ideal control strategy for PPV. Limited naturally occurring resistance genes are available for use in developing highly resistant stone fruit cultivars through conventional breeding techniques. Most cultivars with host resistance henes are tolerant to the disease in that they express few, if any, symptoms but carry the virus. Such cultivars are of limited value to prevent the spread of PPV. Currently, the most promising prospect for PPV resistance is genetic engineering. The insertion of PPV gene fragments into plum trees confers high resistance to PPV through the anti-viral pathways of RNA silencing, a potent natural defense mechanism against viruses in plants. This resistance is heritable and can be incorporated into other cultivars through standard breeding practices. Although this method is still in early, experimental stages, it offers great promise for the development of commercial stone fruit crops that are resistant to PPV.