sign in sign up
<<
Home , Apricot, Apricot (color), Peach (color), Plum (color), Plum pox

Types of Pox Report Infestations Four PPV groups exist to date. PPV-D was originally For more information or to report trees and dis- described from trees in southeastern ; playing signs of , contact one of the follow- PPV-M from trees in ; PPV-EA from ing government agencies: apricot trees in El Amar, ; and PPV-C from sour trees in . USDA-APHIS-PPQ Plum Pox Program Coordinator PPV-M isolates are Invasive and Pest Mgmt more aggressive in 4700 River Road, Unit 134 peach, are Riverdale, MD 20737–1236 vectored more effi- (301) 734–8899 ciently, and spread more rapidly in an Pennsylvania Dept. of Agriculture orchard than the 2301 North Cameron Street D strain. PPV-M has Harrisburg, PA 17110–9408 been reported to be (717) 787–4737 PPV-induced chlorotic rings and blotches on peach fruit transmitted, while other PPV strains are known not to be transmit- FOR MORE INFORMATION and a A Devastating Threat ted through . Both PPV strains M and D infest peach, plum, and apricot. The strain present in PHOTO GALLERY OF SYMPTOMS Pennsylvania has been determined to be PPV-D. visit the USDA web site at: to , , www.aphis.usda.gov PPV-C infects sweet and tart cherry naturally and has , Nectarines, infected other hosts experimentally. To date, no other PPV strains have been reported to infect cherry Photos Courtesy , naturally. Scientists use several techniques to distin- P. Gentit, Ctifl, France guish PPV strains. They monitor the behavior of host M. Nemeth, PHSCS, trees. They conduct serological tests such as ELISA and M. Barba, ISPAVE, and Sweet and Tart molecular tests such as polymerase chain reactions G. Herrera, INIA, (PCR). They also sequence the PCR products or cut the J. B. Quiot, INRA, France PCR products with enzymes at locations in the DNA sequence that are unique to each strain. Department of Agriculture

This informational brochure was produced by The American Phytopathological Society (APS) in coopera- tion with USDA-APHIS-PPQ. You may download a copy of this brochure at the above web site or obtain addi- tional copies from your State Health Director (list- ed on above website).

For more information on plant diseases PPV symptoms on young of peach (top row) and necatrine visit the APS web site at: www.scisoc.org United States For local information on Plum Pox and other diseases Department of contact your state extension service or department of Agriculture agriculture office. Plum pox, also known as sharka, is the most devastating viral disease worldwide of stone fruit including peaches, apricots, plums, nectarines, almonds, and sweet and tart cherries.

The disease signifi- Identification Disease Spread cantly limits stone In peach, PPV-infected Several aphid species can fruit production in trees may exhibit - transmit plum pox within an areas where it is breaking symptoms in orchard and from other trees established. More the blossoms. This to nearby orchards. Long-dis- than 100 million appears as darker tance spread usually occurs stone fruit trees in stripes on the as a result of the movement are infected. PPV ring pattern symptoms on apricot fruit petals and can be useful Example of PPV-induced color breaking (pink flecks) in of infected nursery stock or and stones for early season surveys. certain peach propagative materials. Chlorotic rings and blotches on plum fruits caused by PPV First described on PPV symptoms can be present in young in the plums in in spring and/or on developing fruit. Some trees show no Plum pox is spread from 1915, plum pox has spread to a large part of Europe, symptoms on leaves or fruit. In Chile, several of the infec- plant to plant by several the Mediterranean, the Middle East (Egypt and ), tions have been symptomless, and infections were discov- aphid vectors (insects that , and Chile. In 1999, for the first time in North ered only through rigorous testing of trees. suck sap from then America, plum pox was detected in a Pennsylvania carry the virus to other orchard. Not all PPV infection in plants). spread plum Prunus are character- pox by carrying the virus in a peach aphid, Plum pox is economically impor- ized by a ring symptom non-persistent manner. The tant because it can cause fruit to on leaves. Several culti- length of time the virus remains on the stylet (part of be unmarketable and can vars show yellowing the aphid’s mouthpart) depends on how soon the aphid decrease the yield of infected line patterns and probes a new plant after acquiring the virus from an trees. The severity of the disease blotches, or necrotic infected plant. This means that the virus remains on the depends on the strain of the (browning) ring symp- stylet from minutes to perhaps a few hours. Studies indi- virus present and the susceptibil- Chlorotic ring symptoms caused by PPV in plum leaves toms on expanded cate that at least 14 aphid species can transmit PPV. ity of Prunus cultivars (cultivated leaves. distortion These species include Myzus persicae, Aphis spiraecola, A. varieties of plants). has also been observed. gossypii, and A. fabae. Some PPV strains have been iden- As mentioned above, tified that are not transmissible by aphids. The virus causing the disease is the leaves of some plum pox (PPV). PPV peach trees in France Control infects various members of the Chlorotic ring patterns on leaves and infected with PPV-M genus Prunus, such as the distortion of fruit in apricots infected Control and prevention with PPV produce a yellowing stone fruit trees mentioned vein clearing that turns measures for PPV include above. Wild and ornamental species of this genus may necrotic and causes leaf field surveys, use of certified also become infected by some strains of the virus. Some PPV-induced chlorotic blotches in peach leaves drop. nursery materials, use of weed hosts identified in the field and numerous hosts resistant plants (when avail- PPV symptoms on apricot leaves tested in laboratory settings have also been known to PPV-infected fruit can develop rings or blotches, able), control of aphids, and become infected with PPV. or rings, and some plum and apricot fruit can be elimination of infected trees in nurseries and orchards. severely deformed and bumpy. The pits of many infect- ed apricots and some plums show rings. Sources of resistance exist in Prunus but are not abun- dant. A team of scientists from the United States and Because infected Prunus trees France has genetically engineered a PPV–resistant plum exhibit such a wide range of leaf, (otherwise known as C5), and the resistance can by flower, and fruit symptoms, educat- transferred through hybridization to other plum trees. ing survey crews, diagnosticians, This provides a unique source of germplasm for future growers, and nurserymen to the breeding programs worldwide. Similar success has not Deformed plum fruit caused by PPV PPV-induced chlorotic rings and blotches on yet occurred in attempts to genetically modify other range of possible PPV symptoms is PPV-induced chlorotic rings and peach fruit Prunus species. crucial to detecting plum pox. blotches on nectarine