I was wondering how to stop disease spread on
my friend's/client's property. This is the
first time I will supervise a crew. I am a
certified arborist who is concerned for the
health of the trees. There is already a lot
of secondary wood rot up there and we don't
need it spreading. What should we put on the
blades?? Bleach?? How do we apply??? Any
other known methods??

Thanx

Sara

Reply to post by Sara, on March 20, 1999 at 01:51:07:

I've looked around a bit on the subject of sterilzation of tools;

Alchohol does not work on fungal spores.

bleach works on everything but you need to soak the blde for several minuets between cuts.

A local orchard only does steril pruning on there frut trees when removing fire blight dieback.

That is the general, what are the specifics of your situation? Type of tree(s) and disease problem?

Reply to post by John S, on March 20, 1999 at 01:51:07:

Hi John,

Thank you I will use the bleach. The situation
is a forest that ... 50 years ago was dominated
by oak and madrone with some bay, manzanita,
and doug fir. Well.... fire suppression....
so the forest should have had one to two fires
in that amount of time naturally speaking.
So the doug firs went hay wild and are crowding
out the oaks and madrones. So the property
owner wants me to supervise these guys from
some other company and they are into bidding and
seeing how fast they can cut...know what I
mean??? I am scared. The wood rot looks all to
be secondary. No armalaria or anosis (spelling?)
that I could see. Maybe some black stain...maybe.
The forest was logged 50 years ago (the doug fir)
This is your standard second growth deal hear
not two terribly healthy but could be worse.

That is all the info I have. I will do the
bleach technique..thank you.

Dana

Reply to post by Sara, on March 20, 1999 at 01:51:07:

What are you trying to prevent? THere are certain types of infections known to be spread by pruning tools. However, if you are concerned about general infection by discoloration and decay fungi, the sterilization of tools will have little effect. These fungi are seldom spread by pruning tools, but do readily infect the cuts following the pruning. Sterilization may be an unnecessary expense on our job.

Should you choose to use the bleach, be aware that it is highly corrosive to steel. Suggest adding a rust inhibitor- a bit of radiator antifreeze will help. It contains ethylene glycol, itself a sterilant, and rust inhibitors. Also be sure to clean and oil all tools before storing them.

Reply to post by John S, on March 20, 1999 at 01:51:07:

John, do you have a citation for the statement that alcohol isn't effective as a sterilant against fungal spores. The references I've seen so far seem to contradict that. Thanks.

Reply to post by mark Goodwin, on March 20, 1999 at 22:50:05:

It has to do with the way alchohol works. It is a water scavenger, sucks the water out ok a cell. One reason we would use a 70% vise 99% (HEAT) solution is that the purer stuf will desicate the membrane, damaging it enough to create a barrier that protects the celular media (? man, I'm ten years away from organic chemistry and could be phrasing this a little wrong but the gist is there). On the same note, spores have a barier that prevents the alchohol from doing the job.

With chlorine bleach, as it beaks down nacent O is released (?). O- is very corrosive (we breath O2) and will break down most organic barriers in microbes within 2-3 min.

Can't remember last place I read it so I cannot provide any backup doc.

jp

Reply to post by JPS, on March 21, 1999 at 12:26:28:

In pathology lab we would dip the tools into 75%-95% ethanol, then hold over a bunsen burner or more likely an alcohol lamp flame. This would knock ut spores.

Reply to post by Sara, on March 20, 1999 at 22:50:05:

It sounds like you're on the east side of the Coast Range between Coos Bay and Vancouver Wash. There are some madrone diseases that could spread through tools, maybe. A Phytophthora sp. and a Botryospaeria sp. on foliage & twigs. It won't help any to disinfect tools for someting like that. As someone else mentioned, it is only done commonly for fire blight (Erwinia sp.)

Reply to post by Peter Torres, on March 21, 1999 at 18:34:30:

That doesn't make sense to me Peter, the flame would be doing most of the work, no?

With any sanitizing agent (we don't truely sterilize) it must remain in contact with the organism for a couple of min anyway.

One of my employers had me spraying saws and shears befor each job, remebering my highschool Ag corses I did a little reading up a few years ago. What he was doing seemed to me to be good intentions but wasted effort. Spraying the blades after each job would be better.

If you're realy concerned about contamination, having several tools soaking in 100ppm bleach solution or about 1oz laundrey bleach to 5gal of water (pool bleach is stronger). This way you can soak each for 2 min between cuts.

My sorce for the last paragraf is my father how is a registed Sanitarian with the state of WI for 40+ years, there's no way I'ld know those ratios. He is also the one that insisted on me changing to sanitize, since only an autoclave will sterilize.

jps

Reply to post by John S, on March 21, 1999 at 22:43:06:

Does anyone have references to sanitizing tools really doing any good? It is recommended so often but I have never read any literature that backs up the practice. Like someone wrote, the pathogens will find the wound even if they don't hitch hike on the tools.

I liked the note on sanitize vs. sterilize, good change in terms.

Tom