Potato Review

8 POTATO REVIEW JANUARY/FEBRUARY 2021 VIRUS TESTING The importance of virus testing FERA recently held a potato virus testing webinar in which the company’s Virologist, Dr Adrian Fox, answered questions about identifying viruses and what enabling action can be taken. Here, we highlight those questions and the answers he supplied. Why has PVYnbecome such an issue? PVYNTN rst emerged in Eastern Europe in the 1980s and have gradually become the predominant serotypes across Europe. Whilst there is no clear single reasonwhy this has become the predominant ‘type’ there have been a number of supporting arguments put forward. As ever these are ‘general’ responses and there will be speci c exampleswhere the converse is true, but the two key considerations are (1) these types appear to outcompete theOandNstrains owing to being translocated and transmitted more readily, and (2) there is some evidence that these strains aremore subtle in their expression in a range of varieties, sowill have built up largely unnoticed by comparison to othermore obvious strains. e other key factorwill be the varietalmix being grown, whichhas changed over time. If varieties with a lower susceptibility to a strain are planted this will skew the population in that direction. What PVY strains are prevalent in theUK? e isolate typesmost commonly found in the UK are the EU-NTN types, however we also routinely nd serological PVYo some of whichwill be PVYN- Wilga as conventional O-types. Apart fromPVY, what other viruses are prevalent in theUK? We have potato leafroll virus, but in recent years this has been e ectivelymanaged through chemical control and certi cation. e potyviruses PVA andPVVoccur but incidence tends to be variety dependent. To a lesser extent, PVS andPVMare present. Away fromaphid transmitted viruses tobacco rattle virus andpotatomop-top virus are also present and can cause issues in susceptible varieties. Can sampling for aphid vectors and testing themfor viruses give an indicationof virus incidence in an asymptomatic potato crop during the growing season? No. Sampling and testing for non-persistently transmitted viruses such as PVY is not a reliable strategy. Haith leads the way in design and technology for root crop washing, grading and packing systems. From intake to sorting and automation, food processors and packers worldwide trust Haith to handle it. www.haith.co.uk T: 01302 831911 E: sales@haith.co.uk INNOVATIVE THINKING p08_potjan21.indd 1 17/12/2020 22:15