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How to Save Virus-Infected Varieties; Thermotherapy for Crops · Hydroponics Daily

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  Hello there, and welcome back to
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  Hydroponics Daily, your go-to podcast for everything soilless cultivation.
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  I am your host, Dr. Russell Sharp, the founder of Utreema Limited,
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  a company that makes truly unique fertilizers, biostimulants,
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  and biopesticides that you won't find anywhere else. The technology is completely unique.
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  And today, the topic of the podcast is what I would do if I was faced with a virus in my crop.
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  Specifically a crop where you want
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  to protect the genetic material and
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  you can't just throw the plants away often when
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  we say when you've got a virus the first thing you should do is just destroy all
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  plant material but what if you've got a strain
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  a variety a cultivar that
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  only you've got or is protected or is endangered or
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  you need it for a breeding program or something like that
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  and you need to get rid of the virus what are you going to do you can't give
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  plants tamiflu that technology is not available you can't
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  just wait for their immune system to fight the virus
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  off because they don't have immune systems and so there's only really one option
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  that i'm aware of and that's heat treatment so you when you're planting out
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  cuttings tubers bulbs or seeds immersing them in hot water for a defined period
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  can help with virus control.
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  So we're talking about temperatures of 45 to 55 degrees Celsius.
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  So you wouldn't keep plants, not many plants would live at that sort of temperature,
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  they would soon die off, especially unless the humidity was really, really high.
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  But the duration of which you give this treatment is only like 10 to 60 minutes.
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  So in crops that's regularly, perennial crops, herbaceous perennial crops where
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  they regularly suffer from viruses like sugar cane, sweet potato, banana,
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  even grape vines and some ornamentals, you can do this and with success and control viruses.
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  And you're best obviously doing it with smaller plants because smaller the plants,
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  the more effective the treatment will be because of just the temperature profiles and things like that.
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  Now obviously there's a big challenge there it could
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  be phytotoxic it could just kill your plants from
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  the heat but with a bit of experimentation you
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  could find what is the sweet spot for your particular plant and in fact if I
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  was going to do this if I had a plant that I needed to control the viruses I
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  would do it until the plant breaks so I would get maybe 100 cuttings from a
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  virus infected plant and I'd treat 10 at.
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  What did I say the temperature was, 45 degrees Celsius for 10 minutes,
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  and then all the way up to 10 that would be treated at 55 degrees Celsius for 60 minutes.
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  No idea what that is in Fahrenheit, apologies for American listeners,
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  but it's pretty warm, it's sort of like steam room temperature.
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  So I would do a range and find out at what point did the plants die,
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  and just go slightly below that,
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  and really really stress it, because you don't want any virus
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  particles in that new plant because it will be
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  a source of infection and you will not get
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  a chance to do this twice really so obviously seeds
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  is the easiest but very rarely you won't go
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  on to do that it's after that tubers something
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  dormant a bulb they're going to be much more resistant much more tolerant of
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  those high temperatures whereas a cutting is probably going to be the most sensitive
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  but i would do it until it breaks if you're prepared to lose a few cuttings
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  you could do it on unrooted cuttings and rooted cuttings i'd probably start
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  with rooted cuttings see if you could get away with it because,
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  severely stressing a cutting that's not rooted and then trying to get it to root
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  you know you're not you you're in for a bad case there because you really struggle
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  because it's all the cells are going to be weak and stressed from that heat
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  treatment so i do it on rooted cuttings, newly rooted cuttings,
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  not too much growing media around them.
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  Okay, so that would be my.
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  My suggestion, what are the success rates? If you're doing it on seeds,
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  the sort of typical virus elimination you can achieve is 60 to 90%.
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  Whole plant cure rate, typically around 50%. So you may need to screen the plants
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  and quarantine and destroy any plants that are not completely successful.
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  Micropropagation as well. There's often a technique that's used in micropropagation because you can,
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  these plants are so much smaller than a normal cutting than
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  a normal plant that you can quickly get them to the temperature
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  and then back down again quickly whereas a a large
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  corm or bulb or tuber you could
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  think you can get in the center of that tuber to 50 degrees celsius
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  means much longer and the outside temperature will
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  have to be a lot warmer so so yeah
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  that's probably going to be lower success rate there what
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  else can we say this is sort of the term is thermotherapy by
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  the way so what else can we say about it you can
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  do it on whole plants large plants but you would probably
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  need a grow room dedicated to it with a sort
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  of a temperature of high 30s probably
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  early 40s for two to six weeks that's a
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  lot of heat if you're not in a tropical or arid area but you've got fruit trees
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  large fruit trees ornamentals that are just infected then it might be worth
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  it for targeting systemic viruses and preserving the whole plant structure rather
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  than going back down to cuttings and starting it all over again.
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  The heat stress will reduce the vigour and survival of the plants.
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  You'll probably get some scorching on the leaves and things like that.
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  So if it's an ornamental plant, you might reduce that.
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  The success rates for whole plant thermotherapy are lower. So 30 to 70% virus elimination.
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  And just because the temperatures are lower, so the virus isn't exposed to such a high temperature.
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  And maybe this is why, you know, when you get a virus, like a cold or a flu,
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  your body heats up because viruses don't like high temperatures.
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  But, you know, tropical plants still get viruses. So I'd imagine this is harder
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  to do on tropical plants and easier to do on temperate plants,
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  because tropical plants are going to be exposed to these high temperatures anyway,
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  and the viruses will be adapted to them.
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  It will depend on the virus and its genetics, because even though they're not
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  alive, they have genetics, they have genes, whether that's RNA or DNA.
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  So the virus biology will have an effect and the host tolerance the ability
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  to withstand those high temperatures
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  will be key and the precise treatment i
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  would probably do a water bath would probably be the
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  easiest way to do it with cuttings now a water bath you can set to a set temperature
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  and and dunk them in what's that thing they use in kitchens is it a bain marie
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  when they when they're cooking steaks very precise temperatures you could potentially
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  use one of those as well and or Or if you fail in that,
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  a pot on a stove or something in an oven,
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  some water in an oven that could get the plants to 50 degrees Celsius uniformly.
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  So you don't want to put them in dry heat in an oven because they're exposed
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  to all sorts of temperatures there.
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  Definitely don't just put them
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  in an oven. Definitely use a water bath for cuttings and things like that.
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  So that would be my top tip.
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  Just sort of Google there. You can pick up a Bain-Marie for like 100, 140 pounds.
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  So that's not a lot considering the value if
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  you're going to go to these lengths then the value of these plants must be considerable
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  if you're going to spend the time and effort to try and eliminate viruses from
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  them and potentially you know with virus testing getting better and better and
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  more what's the word i'm looking for accessible you could potentially have a nice little hydroponic.
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  Business selling certified virus-free
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  heat treated cuttings that could
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  be one of the things if you if in your industry cuttings there's
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  a there's a business is selling cuttings and you're looking for a unique selling
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  point then potentially you could say our product our cuttings are all heat treated
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  and checked and checked for viruses before they leave the nursery and that could
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  be a really good small little venture little bootstrapped hydroponic company
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  to get you going up and running,
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  selling, cuttings, and propagation material.
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  Anyway, that's been Hydroponics Daily for today. If you found it interesting,
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  took me three hours and a long journey in an
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  least check out utreema.co.uk for all your amazing.
• 9:07
  Fertilizers, biostimulants and biopesticides.
• 9:09
  None of our products control viruses because you can't control a virus.
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  You have to either destroy your plants or heat treat them.
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  You can use insecticides to prevent the spread of aphids, which transfer the viruses.
• 9:23
  We don't sell insecticides, we sell an insecticide or soap and that's about
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  it. So yeah, that's been Hydroponics Daily for today.
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  Thank you very much for listening and I'll see you again tomorrow.