How you may plan of the preventive measures, in methods' part? All crops bear invasive pathogens which may colonize appropriate local hosts among weeds and local varieties of the main seed crop. Thus you need to survey both pathogens (one list) and develop a list of potential plant hosts (second list). Seed crops are the sluices of invasive pathogens which local targets (=potential pathogens' hosts) are to be predicted but it is not an easy task. Temperature is not only parameter in such modelling.

Hi Alex, my suggestion is not a quick and easy solution, but I think that seed breeders need to use biodiversity as source of defence against pathogens. This includes genetic resources of natural relatives of crop species as well as "old-fashioned" cultivars.

Marcus,

I agree. All ways must be used. I hope we have time to use them. It looks like in a few following years we will see very dramatic changes in Agricultural production across the World with all economic, political and demographic consequences.

Alex

To be honest, I don't think global warming will make the climate ( and hence the pathogen populations) uniform over the globe. Waiting for this to happen will therefore do nothing. In my views, global warming will change the climatic characteristics from what we currently know, and the question is therefore ' can we (reasonably) predict how much?' If wer can do this - and many models provide reasonable scenarios, then the best guess is to go to places where the expected conditions in our places are the current climate, and see what pathogens are there, and how they live/thrive. Quarantine will be as important as it is now, but the foresight study will probably give u some clues as to how to deal with the newcomers when they arrive.

In addition to what the colleagues have suggested, following is a note on future seed production under circumstances of global change especially global warming:

Seed banks in close alliance with other institutions (i.e., botanic gardens), will have to assess new germplasm for adaptation to new ecoclimatic conditions.

Seed banks and botanic gardens are complementary and should have to work closely hand in hand to further both the mission of plant introduction and the global conservation effort.

Didier,

You are right, climate will not be more uniform, it will be less uniform, with hot and wet spots: at 2010 Poland was wet through, and European Russia stay without rain for 2 hottest months. But, we have (in Moscow region) already 20 years of warmer springs and falls (since 1995), 2-months longer frost-free season, and 1-2 additional generations of insect - vectors of plant pathogenic viruses, phytoplasmas and bacteria.(as well as ticks with human pathogens). This winter is 6oC warmer of average, with very high infections level at fall of 2013. We can get outbreak of many diseases at 2014 summer.

Global trade is highly important factor - local stores have potatoes from Egypt (often with Ralstonia), carrots from Belgium, broccoli from Spain, tomatoes from Carribian region, fruits and bananas from South America, South Africa, Asia. Flowers from over the World. Vegetable seeds used in private gardens are produced in Italy, China, California even by Russian seed companies, potato seeds from US... We have data for 3 new bacterial pathogens that have been introduced at 2007-9 and spread across the European Russia in 3-4 years. Only one was from the Quarantine List, but all 3 cause equal economic threat.

Some colleagues from APHIS said that they cannot protect US agriculture under increasing international trade, and have to go to local fields to watch the diseases at the site. EU keeps laboratory in Egypt to test for brown rot all potatoes shipped to Europe. I think that plant pathology is not a national business now, not any more.

Alex,

Sure, you're right about the international trade and its effects on pest distribution. By the way, movements of people have almost the same effects than movement of goods ( see the recent Avian flu crises), so yes, we're in a global world now and we have to adjust to that in terms of prevention and control strategies.

Since your original question was about global warming, let's go back to the climate issue. What I understant from the GIEC scenarios is that it's not only the means of climatic variables that will change ( higher temperatures on average) but also the variances that will increase - meaning that predictability on a 'long term average' basis will become less and less accurate. This is a more difficult issue I think for the anticipation of distributions & epidemics to come.

Re- quarantine: sure, those lists have to be revised periodically... but the economic consquences of putting anything on a quarantine list are so high that when a new critter gets there, its' often too late. Too bad, because the good old saying 'it's better to prevent than to cure' still holds!

Thank you everybody, for your suggestions. I can say that the best that we can do in such situation - forecast the situation with plant pathogens and pests without subdividing them into Quarantine or non-Quarantine organisms, prepare monitoring/diagnostic tools for all of them, and educate growers, extention plant pathologists, breeders, seed marketing people - prepare them for possible results of new pathogens/pests spreading. I see Eastern Europe, including all Russia, as a natural "trials field" - Climate changes are the fastest here, large area under undisturbed eco niches work as accumulator for new species, and plant protection is limited, giving a good chance to estabish local population of new species of pathogens/pests.

Hi again all,

If the issue of climate change and biodiversity of pests is of interest, I suggest you check papers based on long-term aphid catches throughout Europe. This work was carried out during the EU project EXAMINE, and showed that on average over the last 40 or 50 yrs, one new species of aphid a year was recorded in the traps. The new species were primarily Mediterranean ones, suggesting that these species moved North with raising temperatures. For references, check papers by Maurice Hullé, who also published interesting data on aphid diversity and biology changes in polar regions, as possible cnsequences of climate change.

I also suggest the fascinating set of papers by Mike W Shaw and co workers on the succession of Mycosphaerella/Phaeosphaeria species on wheat in Great Britain over the last 160 yrs, based on analyses of the stored harvesrt samples from the Rothamsted long term experiment. There was a clear correlation between species prevalence ( M. tritici/ P. nodorum) and SO2 concentration in the air, the latter being probably related to the rise and fall of the use of coal in the British industry since the industrial revolution. And subsequent research (published in Dec 2013 in Plant Pathology) showed that sulphur and sulphuric acid alter the susceptibility of wheat to both pathogen species. Really nice!

Another good set of papers on this topic was published as a Special issue of the journal Plant Pathology ( available online from their site) dedicated to climate change and plant pathogens.

This all suggests to me that dealing with climate change effects should encompass both short-time (years) and along-time (centuries) effects, and that this cannot be separated from the assessment of human activities, both direct (through movement of organisms with human activities) and indirect (through changes in biotopes and climate).

Thank you a lot! M. tritici/ P. nodorum and SO2 - it explains after all strange difference in some industrial and mostly agricultural regions of Russia and Ukraine that we could see at 1980-s!

Hi Alex

Are there any recorded data on these differneces in incidence and/or severity of these diseases in the different regions, and on air composition? If such data are available, it might be well worth unsing them to confirm or infirm the british observations. This would be a real important contribution towards identifyiong aiur composition as a cause of - and not just an incidental coincidence with- population changes. I'm keen on having a look at such data if any are available.

Hi Didier, I will ask colleagues - at that time we worked on one project, and results were only in reports, but it became open after 1991 - before that I left the project at 1989....

I have been in the international vegetable seed industry for over 40 years, and pathogens would not be my first concern, prolonged drought in the world's seed production areas would be my number one concern.

In California we are experiencing the worst drought in 400 years with only five inches (12 cm) in the last 12 months, and the seed growers have had their irrigation water shut off a few months ago. Also, the climate has radically changed, with much warmer days, and without cloud clover then we have much colder nights, and generally much drier relative humidity. 17 California communities are due to run out of water within a few months, for example, and one of our rivers that feeds most of the lettuce grown in the USA, the Salinas, is dry to the rocks.

California plus the India-Pakistan-Arabia part of the world will experience a rapid and permanent shift in climate, along with the Arctic. We humans will probably need to shift our seed growing ares to where there is reliable water supplies in the future, but where those areas will be located is still uncertain.

However, pathogens already are a major issue for plants reproduced by means other than true seeds, like potatoes, bananas, oranges, etc. We got a pathogen introduced from China on a Rhododendron that is killing our California oak forests, called Sudden Oak Death. And Europe and Australia are having a panic about several viroids that attack potatoes, like the Spindle Tuber Potato Viroid.

I recommend the chapter in Elizabeth Kolber's book The Sixth Extinction, where she writes about humans creating a new Pangaea by moving plants, animals and pathogens around the planet. I consider her book to be the most important written in the 21st century CE so far, with The Carbon Diaries 2015 by Saci Lloyd as the second most important.

Craig, thank you for reference! My colleagues used to multiply seeds of Russian veg cultivars in California at 1990-s, but when I was there at 2005 I could see a little of that production. We have big threat from potato pathogens, but seeds are important source of new pathoges as well, expecially bacteria, phytoplasmas, viruses. Actually, for viruses Russia can be a source itself, because in cool climate plants stay infected but symptomless. Potato viroids are common due to virus-free plants - meristema technology supports viroids multiplication.

Craig, speaking about new areas for seed production I would look to areas of ancient argicultures that were stable for very long time - Minusinsk Hollow in Siberia for an example (farming for 3,000 years). But, political situation, lack of infrastructure and skilled people can be critical for such areas. There are several more good places for seed growing (warm, mostly dry and sunny weather, a lot of water in rivers) at the former USSR (Dagestan, Valleys of Uzbekistan, Kyrgizstan) but all have these limitations (politics, education, infrastructure development).