Sanitizing Pruning Tools

Daniel Lantz said:
Nice thread! I have a lot of orchard pruning customers......I have always used isopropyl, but often wonder if it has any affect on meristems....can disinfectants stop or kill meristematic cellular division?
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According to the literature I've read, the tools ought to be allowed to dry after a soaking sterilization process. The sterilizing agent should not be applied to the tree via the cutting tool.
 
http://baker.ifas.ufl.edu/Horticulture/documents/DisinfectingPruningTools.pdf

The long, the short and the curly of the article is:

"The Disinfection Process

Tools should be brushed clean of dirt and debris before placing in the disinfectant solution. This will allow the disinfecting solution to reach every cutting surface. For chain saws, it is recommended that they be taken apart and both the chain and bar soaked. By having multiple pruning tools, one tool can be soaking in the disinfectant solution while the other tool is used for pruning. Disinfectant solution can be carried into the landscape in a tightly sealed plastic bottle, wide enough so that tools can be dipped directly into it. All tools should then be rinsed with clean water before pruning or allowed to air dry. The disinfectant solution should be replaced at least every ten plants or every two hours. In some cases, tools should be disinfected between each pruning cut. "
 
Update: I have been looking into this further, searching for literature citations regarding tool sterilization in the forestry/ plant health care fields. I actually haven't come up with much surprisingly. Also tried contacting the authors of the Palm paper above but no response as of yet.
In the meantime, the following citation might be interesting:
Bacterial Spores Survive Treatment with Commercial Sterilants and Disinfectants Jose-Luis Sagripanti* and Aylin Bonifacino Appl Environ Microbiol. 1999 Sep; 65(9): 4255–4260.
See it at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC99773/
Basically a lot of the topical "disinfection" compounds don't actually work all that well.

Please: disinfection does not equal sterilization.

If you're trying to get rid of bacteria (non encapsulating ones) and fungal mycelia OK perhaps, but spores (and tough guy bacteria) are a different ballgame. The earlier references (above in this thread) from CDC and from Barbicide refer to a hierarchy of organisms and the difficulty in reaching a sterile condition.

I also have questions about the flaming of the tools. 40 seconds flaming to achieve zero or close to zero CFU (colony forming units) really doesn't say what the temperature of the tool was (I would suggest this is possible to measure using an IR sensing instrument). This matters in a climate like we have here (I am writing you from the Great White North - north of the 49th parallel). I would want to know I am achieving a certain temperature (short of red hot - steel temper eliminating).

I actually still think this arborists' tool sterilization area needs more hard butt science work thrown at it. There is a lot of colloquial information which seems to be floating around. This includes things like the reference (above) to chainsaws (hand held and of course the pole saws (hydraulic or electric like the Oregon ones).

Consideration also maybe needs to be given to the choice of tool we use when working on infected wood - i.e. try and stay with easily sterilizable hand tools and away from powered tools (and perhaps chippers which may spread spores etc. all over the place). There's actually lots to think about here! Science needed.

I'd also like to throw out a challenge to the handsaw and scabbard manufacturers like Fanno/ Silky/ Weaver, etc. Can you make us handsaws that say have a quick detachable handles so the metal blade bit can be heated/ cooked without fear for the plastic/ wooden handle or can be stuck in a bucket of sterilant. It would be possible to place a bunch of blades into the "heater" (another new invention) or the chemical bucket and get the required residence time for sterilization. Heating verified by IR readout - knowing is better than guessing. Snap on another blade and you're good to go in the meantime. Another thought goes to the saw scabbards - I've often looked down at the Silky scabbard velcro-strapped to my leg and wondered what baddies could be hiding in the sawdust and goo in there? Can we make one that's easier to clean/ sterilize? Is some super Mumford inventive-ness needed?
 
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This is a conundrum. So it's winter. We are pruning out fireblight (bacterial infection). We are supposed to prune into unaffected tissue for the final cut on this "infected" branch however, if you need to make cuts prior to your "clean cut" in non-affected tissue, how exactly do we do this with the same handsaw/chainsaw/pole pruner? It's absolutely absurd as far as production work goes to think this is feasible and should be our standard operating procedure. So instead of focusing on "how do we sterilize our tools?" can we discuss "how do we make the tree healthy enough to be exposed to fungus/bacteria/aka life and still thrive in conjunction with these other issues?" In addition to the tool issue, we generally all agree that fruit trees susceptible to fireblight should be pruned in the winter when they are dormant and have the smallest probability of having bacterial infections spread via other vectors. HOWEVER, is there a way we can discuss WHY this is the rule without being viewed as idiots? If the tree is not in flower, we have been debating in the front range of CO why we can't effectively fight fireblight ASAP if it has not yet entered the central leader instead of letting it fester and spread til winter when it's "appropriate". I know there are opinions on both sides of this discussion. But soaking tools for 3-5 minutes between cuts or trees in Lysol or whatever you choose OR heating them is not realistic for job sites (again my opinion). And PS--who in the world soaks a chainsaw in a bucket or bottle of fluid to sterilize it? And then either lets it air dry in sub 32 degree temps (cause it's always cold when we are doing this type of pruning) OR rinses it in water? Yeah right. If you do, please call me to explain WHY we should torcher our equipment for the sake of a sick tree that is probably a result of a negligent homeowner or just a tough year from Mother Nature or because this is a normal issue in all of our environments and Darwinism is coming into play. Scientific recommendations of what we need to do to sterilize or disinfect (whatever you can agree to call it as of this post) versus real life production work are in contention. I personally think whatever we prune/remove is going through the chipper (so airborne spores are going to spread--deal with it), tools are not getting dipped or torched enough to be worth doing it at all due to soaking time requirements and the fact that no crew religiously does this well enough to be able to say they do this etc, so if we focus on soil, mulching, year round watering, and proper pruning techniques (eliminating this sterilization of hand tools and pruning in the winter only) and pruning properly prior to storm damage events, why is this not the rule of thumb? Spraying fungicides or other products is not awesome as an alternative. So if the tree bites the dust, then we remove, grind and replant. I am not willing to soak my MS 200 in any bucket or take a torch to her. And likely she is the chainsaw of choice for larger cuts on these infected trees. Ok I'm done. Please give some realistic advise on here instead of crap no one has the time to do or hopes of someone doing a research paper on it that is not likely going to result in any viable help in the near future. Anyone????
 
So I think "production work" means it take too much time to disinfect; or too many sets of tools, chains, etc.
But what is too much time or $ ?

It seems that means too much time for the price quoted, or too costly for the owner.
Perhaps you just explain the "extra" time required to do the job; then let the owner decide.

Replacing a single tree may be appropriate, but a whole grove might not be.
 
We're the professionals. We're the ones with the higher duty of care to inform and advise our clients, so that they can make informed decisions. We don't get to cherry pick science. We should inform our clients that this is what the most current scientific information says we should do to minimize the spread of infection via pruning tools.

"Mr/Mrs Client, Given the current information on tool sanitation to mitigate the spread of infection in pruned trees, XXXXXXXX is how we are incorporating that information and improved process into our pruning practices, and XXXXX is what it cost to do that." It should be simple enough to figure out the additional cost by the cut/branch/tree/day. Then help the client to develop specifications for the job. Maybe they want tools disinfected/sterilized between cuts/trees. Maybe they don't care and aren't willing to pay for it, and would rather roll the dice on the prospects of future retention of the tree(s) on the site. If they're willing to sign off that having been informed of the risk, they don't want to have tools sanitized/sterilized prior to pruning their trees, then so be it.

Then again, perhaps they do care and are willing.
 
CETC: In regards to Fire Blight (Erwinia amylovora), there's a very good research based (sorry) document from the folks at WSU at:
http://treefruit.wsu.edu/wp-content/uploads/2016/07/Fire-Blight-_2016.3.28.pdf
For your particular situation, maybe first paragraph in section Control Principles - Sanitation would help.
For me it gets down to knowing the tree, the particular pathogen and tailoring a plan accordingly.
Others have stated above they use flaming of handsaws in orchards though, presumably in "production environments". And I personally have walked away from jobs where an owner wanted a quick hack job (and have watched the tree removal three years later). But personally, all I can do is the absolute science-based best I can do for the tree in front of me at the time. So I guess call me "The Aseptic Arborist" . . . :-)
I will say again, I think the time is here for some applied science research and a section in A300 settling good practice in light of what we know now about tree pathogens (way more than 5 year ago and developing all the time).
 
Anything blight-looking that discolors the tips of my fruit trees gets cowboy clipped right off, about an inch or so below the visibly affected ends. I disinfect the clippers before I start, and that's it. They're fruit trees. You whack away at the things every year, anyway, if you actually want fruit. They love it. First apple tree I ever planted I had to whack every damn stem off, about 8" or so, and about a foot and a half off the leaders. Two years later, that 6' tall bastard gave us about a bushel of apples and you couldn't tell that it was near death a couple of years earlier. It's still a great producer. I've since had to do it to numerous apple, pear and peach trees. None of them ever died, and they all came back with a vengeance.

I'm not sure how much hospital care a fruit tree really needs. I've never been tempted to put one under anaesthesia and surgically remove infected bits or keep it on a life support machine during recovery. They're tough, and don't seem to respond well to being coddled, sissyfied or exposed to classical music. In 15 years they'll be yanked out and replaced, but they don't seem to mind.

Is it possible... even if it is a remote possibility... that treating a fruit tree like a miniature Pomeranian fluffy housepet is overkill? I mean, you can replace one with nothing but a reciprocating saw and a sharpened drain spade. Or are we talking about some 40-year-old landscape tree in front of a dentist's office?
 
Couple recent finds regarding disinfection/ sterilization of plant pathogens:

Again, a really good paper with other literature citations contained therein -
https://puyallup.wsu.edu/lcs/wp-content/uploads/sites/403/2015/03/Pruning.pdf
as previously cited in:
http://www.treebuzz.com/forum/threads/disinfecting-saws.30204/

http://apsjournals.apsnet.org/doi/pdf/10.1094/PD-89-0815 See Materials and Methods citing surface sterilization of black knot (experimentally for bacteria??) using 10% commercial bleach (0.5% NaHCl) for 4 min
 
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In tissue culture labs and in microbiology labs a common practices is to dip a tool into 99% isopropyl alchohol, then wave it over a spirit lamp or bunsen burner. The alcohol flares off, but it burns so fast it doesn't take the temper out of the needle/loop/scalpel. This wouldn't work for bits of sawdust, resin etc.

another possibility would be to use a cordless reciprocating saw. You can change blades an about 5 seconds, and blades are cheap enough that having 10-20 blades in rotation would be reasonable.

These spores are not indestructible, otherwise we would be knee deep in them.
 
I remember seeing some time ago a document on medical sterilization (it might have been American College of Pathology Guidelines for Hospitals??) that gave a hierarchy of pathogen types in terms of difficulty to eliminate from medical equipment. Spores are certainly up there but the most difficult to eliminate was I believe Prions - which are protein bits.

I like the idea of dumping a bunch of recip saw blades in isopropanol and cycling them thru use as you prune.

I've also wondered what evils lurk down in my Silky scabbard after a couple of jobs. Easy to clean the saw blade, not so much the scabbard (new design needed?).
 
The Internet says rubbing alcohol takes all of 10 seconds to have kill certain bacteria. Now as ghostice said it's best to know what pathogens you are trying to kill for each scenario and come up with a plan. I don't see why caring with you a small spray bottle filled with isopropyl alcohol would slow the production down dramatically.

As a human we have to live with our conscience, we have to pay bills and feed our family's. So when you work for someone else you might not have the luxury to take time to sanitize certain cuts. The only thing you can do is educate the owner of the trees, your employer and do your best. it would be one hell of a choice to quit your job over something like that. I have ran into people that don't care about anything but getting their view back and it doesnt matter what you have to do to the trees, as long as they have their view. I hate those situations and have seriously considered turning those jobs down. After some deep thought I think of it this way, I know i will do the least damage to the trees, and will give the trees the best chance they have. Luckily almost all my customers are amazing and they trust me 100% with thier trees and I can do what ever I need to, to finish the job.

The reason I have been interested in cleaning tools is that in my region slim flux runs rampant in our mesquite trees and I am trying to come up with the best possible program I can for those infected trees.

Does anyone have any insight into slim flux?
 
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