Preferred method to sanitize tools?

The microbiology nerd in me coming out… contact time is important.

If you’re spraying alcohol, or a dilute bleach solution, on implements and immediately wiping it off… you may be cleaning the instrument, but you likely are neither sanitizing or disinfecting it.
Depending upon the ‘disinfectant’ you’re using, necessary contact times may be anywhere from 30 seconds to 30 minutes. Accumulations of organic material on blades, etc. will tie-up or inactivate many disinfectant solutions, so if there is gross contamination of surfaces, you’ve got to first remove the grossly visible organics in order to effectively disinfect the metal surfaces.
Effectiveness of rubbing (isopropyl) alcohol is debatable, with regard to its ability to reliably ‘kill’ plant pathogens on pruning tools, but it’s cheap and readily available in a RTU form.

How do I sanitize my pruners to prevent the spread of disease? | Horticulture and Home Pest News.

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I put a spray head directly screwed onto a bottle of isopropyl alcohol 70%. Those bottles have the same threads as spray bottles.

I believe I saw reported from a study that 70% is more effective than 90%, but don’t feel motivated to look for it right now. It’s memorable because its not super intuitive. Maybe because it takes longer to evaporate, or different surface tension for penetration or something.

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Hydrogen peroxide and urban water with chloramine already in it.

Spray the cut not the tool. I keep my pruners clean with a piece of flat carbide, cut with one hand, spray with the other. I mix Kocide with Bravo or Topsin M with a surfactant in a hand spray bottle. Sometime I use a 10% bleach solution or hydrogen peroxide or peracetic acid.

I’m not sure spraying the cut does anything to reduce the spread of disease/viruses. And doesn’t that damage the cambium at the cut and lead to slower healing?

i might very well be wrong. But if never seen or heard of anyone doing it. So it peaks my intrest.

This is a good topic. I had always been cleaning my shears and grafting knife by spraying the blades with 70% alcohol as many have mentioned above. Today I went to a field trip to the UCR CCPP (citrus clonal protection program), the source for all ceritfied disease free budwood to use for citrus grafting.They had all their experts and lab technicians giving talks of how they clean the budwood, etc. I asked them about what I should use to clean my cutting tools and grafting knife. Here’s what they said:

  1. Alcohol does not clean/kill any of the baterial/viruses, just good for cleaning the blade.
  2. They said must use chlorine (10-20% concentrate). Dip and leave in a jar for 5-10 minutes. So, they suggested to use multiple shears or knives so one set can be soaking while I use the other set.
  3. When you take the cutters out from the chlorine jar, wipe it clean before using it.

So, I guess now I will have a jar of chlorine to disinfect the knifes and shears when going from one rootstock to the next for grafting.

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this is great information, thanks for posting.

Could you tell us more about how they clean their budwood etc?

Is there any research based evidence on benefits of sterilizing pruning tools? As far as I know, commercial growers do not bother and if such a procedure was needed it would seem to be in fruit production of commercial scale- it is like a virus on a cruise liner- so many trees of a single species clustered together.

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Out of curiosity, you as a professional pruner.

Do you disinfect between pruning tree’s?
What if you cut trough a diseased branch? (where there is discoloration of the wood for example? Or when removing fire blight?
Or not at all?

Read this article with research references from over the years on sterilization of tools.

I am referring to research related to commercial fruit production. Linda Chalker Scott is an interesting source of info, but not one to interpret the practicality of methods to be used in commercial fruit production and that is more or less the holy grail for me. Commercial growers have to constantly assess the cost of various maintenance practices and are driven by bang for the buck. If they don’t deem frequent sterilizing of pruning tools as a cost effective practice, the odds are good it isn’t. Of course there are going to be exceptions due to certain diseases in certain sites and regions but I don’t believe it is practical to bother with here in S. NY. I trust the trees to their own wound healing chemistry.

Oscar, fireblight is not a very big issue in all the orchards I manage in NYS and CT. It comes and goes mysteriously and even in orchards where I don’t cut out cankers in big wood, at the customers request (when they don’t want to pay for it) it tends not to show up in subsequent years. Most of the FB I see is only on the ends of shoots, so I try to cut far enough below infected wood not to contaminate my pruners. I have observed no consequences in doing it this way- FB just hasn’t been a big issue here in a single orchard I’ve managed in the last 30 years, except on a few isolated trees. Out of thousands of trees that I prune every year I think I’ve lost about 4 to fire blight- all susceptible pear varieties- either Bosc or Seckel. However, stricken pears almost always completely recover. Where I’ve not sterilized my pruners FB has never subsequently spread the following season- it has never even appeared at any orchard I mange 2 years in a row, that I remember. When it has reappeared at all it tends to be on a previously infected tree, but at least 2 years later.

I do get shoot-blight in orchards fairly often, but it very rarely spreads to larger wood. I remove stricken shoots when they appear. Even when there’s quite a bit of it, it never has appeared in the following year in the same orchard. I’m sure this isn’t the case elsewhere.

I never sterilize my pruning tools and the only possible consequence I can think of may be with the removal of black knot from plums. I tend to spray the wounds with chlorothalonil instead of sanitizing my tools, but this doesn’t always stop wounds from reinfecting, but there’s not much to do about that. I’m going from one infected tree to another so I don’t see how sterilizing the tools would be helpful. .

Then have you ever heard of Kocide (copper) or Bravo (chlorothalonil) or Topsin M (Thiophanate-methyl) spray ever damaging pruned trees. Many prune their trees followed by spraying them.

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Keeping pruning tools clean from sap buildup is job one. Add your favorite sanitizer and get the work done without over thinking it.

Yes, it was very interesting. I think I can do the shoot tip grafting (STG) method of introducing new varieties. But a private hobbyist wouldn’t have the equipment and lab to do the actual testing for the varies disease/virus that hey need to test for every new introduction.

You can go to Fruitmentor (Dan Wiley) on YouTube for all the videos he makes for the CCPP program. This video below is the same thing that was shown to us with the actual material and technique was discussed.
Preparing Citrus Budwood for Shipment - fruitmentor™

We met with the person in charge of the CCPP for California, his name is Georgios Vidalaki. He is the main guy, Director of CCPP. He had his entire staff (technical experts) set up tables for the different topics they covered. It was a demo/seminar, 2 hrs of question & answer. Then 2 hrs field trip to walk through their research field (R&D) of unrelease new varieties.

The program was started in 1907 at the site we visited. They have the clean room lab (not open to public) and the grove nearby that is the research grove for new varieties we visited and tasted fruits from each tree. I have been buying budwood from them for the last 30 years and it was nice to finally go visit their center. This trip was sponsored by our CRFG club, Orange County.

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For seeds, I did ask them a few times, how long will their cleaned seeds last in storage. They said only 4 months is the recommended time to keep them stored in the refrig. They have the same cleaning as budwood, with chlorine, then let it dry, then put it in a bag for storage after thoroughly dry in air. Here’s the photo of one seed bag they had on display. These are the clean seeds that will be used for their sterile test tube to perform the STG. They graft those new shoot tips (introduction variety) on newly grown seedlings in the tube.

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