Date: Wed, 5 Apr 2000 08:41:24 -0700 (PDT) From: Barry Meyers-Rice <bamrice@ucdavis.edu> To: cp@opus.hpl.hp.com Message-Id: <aabcdefg1023$foo@default> Subject: killing wildland D. capensis weeds.
Hi Kevin,
You've got some interesting suggestions, and "thinking outside the box" is
a good approach. Manipulating soil nutrients like you mention has been
done in some weed control programs. I'd be cautious about throwing
fertilizer into this pygmy forest, though, because it is a very nutrient
poor environment. Adding much in the way of nutrients would really change
the character of the habitat, and might kill a large number of the
natives which are also adapted to low nutrients---recall the native D.
rotundifolia? The plastic sheet method you mentioned, often called
"solarization", is essentially a scorched earth policy that hammers
everything under the sheet. Erosion can set in afterwards. This is usually
only done in places where the weed has formed a complete monoculture.
I don't know the effect that pyrethrin insecticides (while bad for the
plants) would have on the native insect populations. This would have to be
researched first.
See, this is a tricky business. The best thing to do is to encourage
people not to do this sort of thing (i.e. plant "introductions") in the
future!
Barry
P.S. By the way, don't be too fast about putting Agent Orange and 2,4-D in
the same mental box. 2,4-D *was* a component of Agent Orange, but not one
of the reasons that Agent Orange was so bad on humans. If I recall
correctly, 2,4,5-T (maybe it was 2,4,5-D?) was also in Agent Orange, and
this compound was laced with dioxins because of its manufacturing process.
2,4-D does not have the same problem, and since it breaks down very
rapidly (in about 10 days) it is actually quite useful for weed control in
wildland settings. I would be surprised if pyrethrins broke down as
rapidly!
--------------------- Dr. Barry Meyers-Rice Assistant Weed Specialist
The Nature Conservancy 530-754-8891, bazza@ucdavis.edu
http://tncweeds.ucdavis.edu
> In this case thinking o/s the box might help. Try Nitrogen, or
> Calcium. In medium sized doses it is fatal to Drosera. A small
> amount of incidental damage will heal its self in 1 or 2 years
> and it wont linger in any harmful way like say agent orange or
> 2-4D. will. Pyrethrum esp. when mixed with citrus oil also is
> known to clobber Drosera but will need to be used a few times to
> really ko the plants.
>
> chances are you will end up with twice as many next year as you
> start with. You might try covering them with a PVC sheet clear or
> black and cooking them in the sun. Remember not all the earth
> takes as long to heal its self as an alpine meadow. Given a chance
> life takes hold. Thats why we even have weeds to begin with.
>
> The real question is how to kill the seed?
>
> krs
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