Maria Erokhova, Junior Researcher, FGBNU VNIIF
Maria Kuznetsova, Head of the Department of Potato and Vegetable Diseases, Candidate of Biological Sciences, FGBNU VNIIF
Continuation of the material. Start: Potato Y-virus: a summary of the latest information
Recently, viruses have become extremely harmful potato pathogens in Russia.
On April 14, 2020, the World Potato Congress hosted a webinar entitled Potato Viruses: The Latest Information. Recording of the webinar in English in the public domain has already been posted on the website World Potato Congress.
The host of the webinar was Dr. Alexander Karasev. He is a recognized specialist in the field of phytovirusology. Alexander Karasev received a Ph.D. in biological sciences from Moscow State University. M.V. Lomonosov majoring in virology. Since 2006, he has been working at the University of Idaho (USA).
During the webinar, Dr. Karasev paid attention to the description of economically significant viruses, among which he named Potato y-virus, potato leaf curl virus (PLRV), tobacco rattle virus (TRV) and potato top panicle virus (PMTV).
The scientist noted that the panicle virus of the top of the potato causes yellow mottling on the leaves, especially on the lower ones, as well as V-shaped marks on the leaf segments. In addition, PMTV causes shortened shoots. Some varieties in the tubers form inner brown arched stripes. Necrosis may or may not be visible on the surface of the tubers. If the affected tubers are planted, the virus is transmitted to less than half of the daughter tubers.
The tobacco rattle virus on the leaves may appear as mild mottling, but these symptoms are not always noted. On tubers, TRV may appear as necrotic arched stripes and spots in the flesh. The severity of symptoms may vary. Many TRV-infected tubers give rise to plants lacking the virus. TRV is distributed with nematodes. The development of nematodes is favored by sandy soil. They spread with surface water and when moving soil.
When plants are affected by the potato leaf curl virus, leaf curl occurs. They may turn red or turn purple. Plants become pale yellow, their growth slows down. A brown streak forms in the tubers in the region of the vascular ring. Such a symptom on tubers is called "net necrosis." Sources of infection are seed tubers, “volunteer plants”, in addition, PLRV is tolerated green peach aphid.
It is worth noting that the listed potato viruses (Y-virus, potato leaf curl virus, potato top panicle virus and tobacco rattle virus) in 2019 received the status of regulated non-quarantine pests for seed potatoes in the EU, which triggers the adoption of more stringent control measures against them in European countries.
As part of integrated protection, the author of the webinar proposed the removal of sources of primary infection, vector control, proper sanitation during manual and mechanized work, the cultivation of resistant varieties and the use of healthy certified planting material grown from meristemic potatoes.