[Fwd: Further Seaweed Theories]

Sorry addressed theis incorrectly

--
Tony & Moira Ryan <theryans@xtra.co.nz>
Wainuiomata,
New Zealand (astride the "Ring of Fire" in the SW Pacific).





Jerry Heverly wrote:

> I would demur on several points:
> 1.  That there are no 'organic' remedies for black spot and rust of rose.
> I could spend a couple paragraphs on the ambiguous definitions of 'organic'
> and, even, 'remedy' but. leaving that aside I'd only say that there are a
> jillion organic remedies for these maladies including: neem oil; baking
> soda and superior oil; sulfur; anti-transpirants; water{i.e. washing off
> the spores}; micro-climate modification{increased air-movement, mostly).

Hi Jerry

I think the question as asked was whether there were any effective remedies for
rust fungi _in general _  and while the various measure you suggest all  give
some measure of control, I have never found anything so far which I would call
really effective. Mind you, I have not heard of neem oil being used as a
fungicide (it is certainly an effective insecticide against codling moth), and
will be interested to try this in my coming summer.

If dealing with rose rust specifically there is one genuinely effective remedy,
which can stop infections for the whole season and that is to seek out and
destroy all the leaves bearing the cluster-cup stage of the rust. These appear
commonly on a few leaves only, shortly after they unfurl in spring and if
scrupulously removed and destroyed simply stop the infection in its tracks.

>
> 2.  increased health=increased resistance to disease.  Again I could
> nit-pick(What is 'health' as applied to non-sentient beings?) but lets skip
> that, again.  There are some cases where avoiding stress on the plant
> system seems to decrease the chances of disease but there are plenty of
> other examples of optimum health leading to *increases* in pest
> problems(the classic being homopteran insects like scale and aphis).

I can't see why  "health" is a concept which can be applied only to sentient
beings. To me it means a living system in perfect tune, whether the individual
is  capable of being aware of it or not.

I would certainly also contest your opinion, that optimum health increases pest
problems, in the light of experience in my own garden.

One of the best examples I can give is the cabbage (brassica) aphis. The only
places I have seen this in my (totally organic) garden is very occasionally on
young transplants and again on very old plants. In the case of the young
plants, it has invariably been on an individual which was lagging behind its
fellows. (what in animals would be called the runt of the litter). I have
always dealt with such an outbreak very simply by simply wiping off the colony
and then improved the health and vigour of the plant with a  spray of fish
extract or something similar and have had no further trouble

Apart from this occasional outbreak, my brassicas (mostly broccoli) generally
go right through their develoment without any aphid attack unless I leave them
eventually to go to flower (for the pleasure of the bees). More often than not
the ageing leaves below the inflorescence become heavily infested, but I have
never seen these colonies spread to neighbouring young vigorous plants, even if
these were growing right beside the oldies (I do not make any attempt to
control these outbreaks, as they must provide useful food for beneficial
insects.)

My opinion does not rest merely on observation, but has an explanation in some
experiments done in France before the middle of the century. (forgive me for
lack of details but I am pressed for time). The gist of this investigation was
that plants in which for any reason the metabolism is faulty  tend to
accumulate unused ammino acids (the "building blocks" of new protein) and this
is what makes them so attractive to pests. How the pests sense this, I don't
know. Perhaps the unhealthy plants smell different.

> 3.  The whole seaweed mystique seems to be based on the cytokinin reaction
> that someone else alluded to.  It's doubtful that there is any significant
> nutrient absorption from a spraying of Maxicrop or any kelp product. Both
> powdery mildew and rose rust are endomorphic fungi which invade the plant
> very superficially and are, therefore, highly susceptible to any
> coating(neem oil, anti-transpirants, seaweed muscilage) that blocks access
> to the leaf.  I'd wager that if you took ten plants and sprayed half with
> Maxicrop and half with dilute soybean oil that you'd get virtually
> identical results with both.
>
> I think you are lmost probably right about this, that the effect of seaweed
> is mostly a mechanical one of blocking access to the leaf surface, rather
> than some tonic effect on the epidermal cells.

Moira
--
Tony & Moira Ryan <theryans@xtra.co.nz>
Wainuiomata,
New Zealand (astride the "Ring of Fire" in the SW Pacific).

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