Re: email list suggestion - organic or not .....
"Randall, Rod" wrote:
>
> I have to agree with Charles here
> DDT and the very usefull organo insecticides were basically banned
> due to public and political pressure, not because any good science that
> showed
> conclusively they were "not safe".
Hi Rod
As I understand it, not only was the accumulation of DDT in fatty
tissues of many species including man found to be harmful (I think
Rachel Carson actually chronicled at least one human death), but overuse
lead to increasing resistance in the insect population and the
effectiveness gradually fell off (we never did get rid or Malaria even
where DDT was extensively sprayed for several years).. I won't go into
its effect on birds here as Toni has already dealt with it in her
posting to Chas.
However, you are not entirely right. It was eventually possible to prove
them unsafe by good science and not merely by public hysteria.
In the case of the organo-phosphates. Several have always been
recognised as too poisonous to be entrusted to the home-gardener, but
the ones which the public is permitted to use are not always all that
safe. In the 50s or early 60s I still remember a case reported in a
local paper of a teenage boy who sprayed the roses with the
currently-available version of this chemical group. He intended to
surprise his mother and certainly succeeded, poor lad, when she returned
home to find him dead.
> Any chemical, even salt, is not safe if abused and thats certainly what
> was happening with all 'cides 20+ years ago.
Do You really think Rob the situation is any better today?
What about the American towns which are up for expenditure of millions
to remove the polluting Diazinon from their water supplies (can supply
chapter and verse if you want)
What about the properties damaged by spraydrift from herbicides. We had
a case here about ten years ago, which I investigated myself, where the
guilty operator was employed by the local city council and should
certainly have known better than to spray in a breezy day (well,
shoudn't he?)
What about the well-documented NZ case reported a couple of years ago
where a man who was severely allergic to many spray chemicals tried to
farm avocados organically, but was driven off his farm when his health
was affected by the frequent spray drifts coming from his neighbours.
You are suggesting that if they were correctly used these chemicals
would be safe, but how in the world are you going to ensure this when
many of the most dangerous are sold to third world countries and applied
by illiterate and ignorant workers, who are not enlightened as to their
danger by their bosses. Even in more educated countries some operators
may be careless due to familiarity or a macho self-image. As to the
general public, while in many countries a saner approach is gradually
prevailing, many tales of neighbours of my correspondents in the United
States persuade me that the general public there is one of the major
offenders, responsible for growing groundwater pollution and
exacerbating allergies and worse among their neighbours. I gather for
instance the Diazinon problem I mentioned above is almost entirely
caused by gross overuse of the chemical for suburban lawn pests.
And finally, if these chemicals are so safe when used correctly, howcome
that most commercial operatives turn out to spray looking as though they
were about to take a stroll on the moon?
If you look at the labels of many of these problems the health warnings
they carry certainly put one off using them unless one has a death
wish..
> Charles is also correct about the insects.
> If a population has no resistance to a 'cide, ie not even one individual
> expresses any level of resistance then widespread resistance can never
> develop.
If a population had no resistance at all, I guess the 'cide would
rapidly kill the lot, and I grant you this has probably never happened.
However, whether it is inborne or simply develops by appropriate
mutations the fact remains that resistance DOES develop, and, if we are
to believe the researchers, with increasing speed, so each succeeding
spray generation remains effective for a shorter time than its
predecessor.
> ,
> Resistance to 'cides is very widespread because of the abuse of these
> 'cides. I inlcude herbicides, insecticides and fungicides as well as
> antibacterials.
> Large numbers of plants, insects, fungi and bacteria are all developing
> resistance to various 'cides and many develop cross resistance to several
> groups of 'cides that use different modes of action negating the best
> efforts of
> researchers. One of the biggest costs to farmers in the western world is
> 'cide resistane in weeds and insects. It adds tremendously to the costs of
> primary produce all because these farmers did not realise that dependance
> on a couple of 'cides would result in massive selection pressures that in
> less than a decade would render that 'cide useless.
All this is very true, and has led a number of thinking people to
question the effectiveness of a policy which makes the farmers steadily
poorer and the chemical companies equally steadily richer, while at the
same time causing horrific environmental pollution and not even dealing
with the problems very effectively.
>
> Integrated pest management is the answer but if hospitals can't manage
> resistant bacteria (human lives are at risk here) then I don't hold
> out much hope for the farmer.
Integrated pest management is certainly a first step to a saner world.
However, in many cases one can go a lot further, even on a commercial
scale, and do away with spraying altogether. To give you a couple of
examples.
One of the major insect problems faced by orchardists in NZ is the
codling moth. Untreated it can take up to a horrifying 80-90% of the
crop.
Spraying, which needs to be carried out at leat eight times each season,
can alter the percentage to about 90-95% sound fruit. However, this is
very hard on other denzines of the orchards, including actively helpful
ones. Such an organism is the predatory mite which keeps its pest cousin
in order. If it is killed off by sprays the pest mite multiplies,
causing severe tree damage and necessitating yet another round of
spraying.
Organic growers will avoid using any spray, however mild, if an
alternative treatment can give the required results and In NZ it has
been found that filling the orchard with twists of plastic impregnated
with the pheremone of the female moth so confounds and bamboozles the
males that they never do find the females to mate. The results from this
treatment have been as effective as all that complex spray routine and
without in any other way affecting the ecology of the orchards. As you
can imagine they are being increasingly adopted for commercial organic
apple growing..
My other example refers to brown rot of peaches and comes from
California. Even with rigorous spraying a loss of around 30% from this
disease is expected. In an experiment an orchard was heavily mulched
with compost and no spray was applied. At the end of the season two
adjacent orchards conventionally sprayed had their usual percentage of
rotten fruit while the compost-mulched orchard had NO BROWN ROT AT ALL.
That's right, NONE.
This sure sounds like muck and magic, but the experimenters did come up
with a possible explantion. They found that the mulched trees had a
considerable growth of a harmless yeast over their branches and they
surmised this had protected the surface of the developing fruitlets from
attack. In fact compost teas have been found to give protection of
foliage from several diseases, presumably due to yeasts or other
organisms they contain.
> History has proved more conclusively than anything that very few people
> really follow the instructions on 'cides seriously, especially application
> rates,
> disposal and mixing requirements or ever read the cautions about when you
> can and can't apply the 'cide.
>
> So next time you buy a 'cide use it as per the label please.
Or better still don't buy it at all! If you are not too bothered by
drift from the neighbours it is possible within a few years to bring any
home garden to a state of natural balance (as I have done in my own
yard) where most of the time pests and diseases are so minimal you can
ignor them and usually if any control is ever needed you can use some
routine other than spraying a chemical. Moreover, if you _do_ have to
spray you can mostly use simple safe materials out of your kitchen like
cooking oil or baking soda. About the most severe spray I ever use
nowadays(very rarely indeed) is neem oil. Neem is a plant extract which
is safe enough for humans for it to be incorporated in toothpaste used
in India. as far as the insects are concerned it only disrupts the
development of larval stages, so is mainly useful against caterpillars
(lik those of codling moth). It should never, however be sprayed over
open flowers, for fear it might contaminate honey and pollen and so
become dangerous to bee colonies..
Moira
--
Tony & Moira Ryan <theryans@xtra.co.nz>
Wainuiomata, New Zealand. (on the "Ring of Fire" in the SW Pacific).
Lat. 41:16S Long. 174:58E. Climate: Mediterranean/Temperate
