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Old 24-11-2007, 04:59 AM posted to aus.gardens
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Default beware pyrethrum sprays

In early spring my Mum enjoyed the butterflies frolicing among the spires
of colourful blooms on her snapdragons. Then she realised it was not the
nectar they were coming for--the blossoms were being shredded by hundreds
of caterpillers! Not the leaves, just the delicate blooms.

So I sprayed the flower heads with a ready-to-go pyrethrum spray. Two
days later the blooms had turned brown, burnt by the spray! So she cut
off all the flower heads and hoped that more would develop. But ten
days later the spires of leaves showed severe burn and the plants had
to be cut back to near ground level. Maybe there is still a chance they
will reshoot this season.

I didn't see any warning on the pack label that plants could be burnt
by it. I did apply it generously hoping for a quick kill, but didn't
read any caution about being heavy handed. So be warned.

I've suggested Dipel or Success for future combat.
--
John Savage (my news address is not valid for email)

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Old 06-12-2007, 12:32 AM posted to aus.gardens
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Default beware pyrethrum sprays

Do you use the spray during the day?

I used a similar spray and it ended up burning my roses - but it was on
account of the sun's heat. If I had done it in the evening or very early
morning it doesn't happen.

BD

"John Savage" wrote in message
om...
In early spring my Mum enjoyed the butterflies frolicing among the spires
of colourful blooms on her snapdragons. Then she realised it was not the
nectar they were coming for--the blossoms were being shredded by hundreds
of caterpillers! Not the leaves, just the delicate blooms.

So I sprayed the flower heads with a ready-to-go pyrethrum spray. Two
days later the blooms had turned brown, burnt by the spray! So she cut
off all the flower heads and hoped that more would develop. But ten
days later the spires of leaves showed severe burn and the plants had
to be cut back to near ground level. Maybe there is still a chance they
will reshoot this season.

I didn't see any warning on the pack label that plants could be burnt
by it. I did apply it generously hoping for a quick kill, but didn't
read any caution about being heavy handed. So be warned.

I've suggested Dipel or Success for future combat.
--
John Savage (my news address is not valid for email)



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Old 06-12-2007, 11:30 AM posted to aus.gardens
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Posts: 186
Default beware pyrethrum sprays

Maybe you burnt them due to the gas being a sort of refrigerant. In
other words youre spraying a bit too close to the plants.
Do it when there is no winf ie early in the morning when theres very
little wind. Then you can spray them with some distance in between.

Blackadder wrote:
Do you use the spray during the day?

I used a similar spray and it ended up burning my roses - but it was on
account of the sun's heat. If I had done it in the evening or very early
morning it doesn't happen.

BD

"John Savage" wrote in message
om...
In early spring my Mum enjoyed the butterflies frolicing among the spires
of colourful blooms on her snapdragons. Then she realised it was not the
nectar they were coming for--the blossoms were being shredded by hundreds
of caterpillers! Not the leaves, just the delicate blooms.

So I sprayed the flower heads with a ready-to-go pyrethrum spray. Two
days later the blooms had turned brown, burnt by the spray! So she cut
off all the flower heads and hoped that more would develop. But ten
days later the spires of leaves showed severe burn and the plants had
to be cut back to near ground level. Maybe there is still a chance they
will reshoot this season.

I didn't see any warning on the pack label that plants could be burnt
by it. I did apply it generously hoping for a quick kill, but didn't
read any caution about being heavy handed. So be warned.

I've suggested Dipel or Success for future combat.
--
John Savage (my news address is not valid for email)



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Old 06-12-2007, 07:04 PM posted to aus.gardens
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Default beware pyrethrum sprays

g'day john,

might be the difference between natural pyrethrum and the man made
version??

the natural stuff very expensive but ultimatlely the safest, organic
farmers can only use the natural product last i heard.

On Sat, 24 Nov 2007 04:59:57 +0000 (UTC), John Savage
wrote:
snipped
With peace and brightest of blessings,

len & bev

--
"Be Content With What You Have And
May You Find Serenity and Tranquillity In
A World That You May Not Understand."

http://www.lensgarden.com.au/
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Old 06-12-2007, 07:06 PM posted to aus.gardens
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Default beware pyrethrum sprays

anotehr to consider jonno,

when i used to spray i always did so after the heat of the sun, in the
afternoons or early evenings.

and aerosol cans carry the added down side that the propelants could
cause plant damage.

On Thu, 06 Dec 2007 22:30:16 +1100, Jonno snipped
With peace and brightest of blessings,

len & bev

--
"Be Content With What You Have And
May You Find Serenity and Tranquillity In
A World That You May Not Understand."

http://www.lensgarden.com.au/


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Old 07-12-2007, 10:19 AM posted to aus.gardens
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Default beware pyrethrum sprays

Thats what I meant to say Len, The propellant is a gas, (butane I
believe) and that when its released acts as a refrigerant, It cools
things donw rapidly. Same as filling a gas bottle, you see frost form on
the surface. IE can cause cold burns on plants. The same as heat burns.
Whether there is a difference in early morning or late spraying, I dont
know...

len garden wrote:
anotehr to consider jonno,

when i used to spray i always did so after the heat of the sun, in the
afternoons or early evenings.

and aerosol cans carry the added down side that the propelants could
cause plant damage.

On Thu, 06 Dec 2007 22:30:16 +1100, Jonno snipped
With peace and brightest of blessings,

len & bev

--
"Be Content With What You Have And
May You Find Serenity and Tranquillity In
A World That You May Not Understand."

http://www.lensgarden.com.au/

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Old 09-12-2007, 04:36 AM posted to aus.gardens
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Default beware pyrethrum sprays

"Jonno" wrote in message
u...
Maybe you burnt them due to the gas being a sort of refrigerant. In other
words youre spraying a bit too close to the plants.
Do it when there is no winf ie early in the morning when theres very
little wind. Then you can spray them with some distance in between.


Oh no. I use the hand pump manual add ons. I don't use a spray can.

Its just the heat of the sun. Even if you just spray cold water on the
plants- the sun magnifies the droplets and burns the plant.


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Old 09-12-2007, 05:55 AM posted to aus.gardens
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Default beware pyrethrum sprays

The water on the leaves story has been around for some time, and been
investigated. The problem is really caused by fungal infections due to
water on the leaves. The sun does not magnify due to different focal
lenght. But plants can suffer from straight out sunburn....Tomatoes for
instance get sunscald.

I'll try and find the story again if I can...

I wonder is some plants are susceptible to the pyrethrum?


Blackadder IIVX wrote:
"Jonno" wrote in message
u...
Maybe you burnt them due to the gas being a sort of refrigerant. In other
words youre spraying a bit too close to the plants.
Do it when there is no winf ie early in the morning when theres very
little wind. Then you can spray them with some distance in between.


Oh no. I use the hand pump manual add ons. I don't use a spray can.

Its just the heat of the sun. Even if you just spray cold water on the
plants- the sun magnifies the droplets and burns the plant.


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Old 09-12-2007, 10:09 AM posted to aus.gardens
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Default beware pyrethrum sprays

Here's a link and part of a theory, which backs up what I read.

http://cahe.nmsu.edu/ces/yard/1999/062899.html

But wait I think there's more...

Jonno wrote:
The water on the leaves story has been around for some time, and been
investigated. The problem is really caused by fungal infections due to
water on the leaves. The sun does not magnify due to different focal
lenght. But plants can suffer from straight out sunburn....Tomatoes for
instance get sunscald.

I'll try and find the story again if I can...

I wonder is some plants are susceptible to the pyrethrum?


Blackadder IIVX wrote:
"Jonno" wrote in message
u...
Maybe you burnt them due to the gas being a sort of refrigerant. In
other words youre spraying a bit too close to the plants.
Do it when there is no winf ie early in the morning when theres very
little wind. Then you can spray them with some distance in between.


Oh no. I use the hand pump manual add ons. I don't use a spray can.

Its just the heat of the sun. Even if you just spray cold water on the
plants- the sun magnifies the droplets and burns the plant.

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Old 11-12-2007, 03:04 AM posted to aus.gardens
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Posts: 48
Default beware pyrethrum sprays

On Dec 6, 11:32 am, "Blackadder" wrote:
Do you use the spray during the day?

I used a similar spray and it ended up burning my roses - but it was on
account of the sun's heat. If I had done it in the evening or very early
morning it doesn't happen.

BD


Pyrethrins are also quite oily which probably intensifies the problem
of spraying in hot weather.


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Old 12-12-2007, 09:13 AM posted to aus.gardens
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Posts: 186
Default Some myths regarding gardens or Old Wives tales debunked. myth busters'R us

EXAMPLES OF GARDEN “MYTH”-INFORMATION



Myth #1 Companion planting improves plant growth.

Originally based on folklore and tradition companion planting has lots
of supporters. Some research done in the 1930’s used chromatography from
plant mixtures and evaluated the color patterns they made to determine
if they were a good match. (“grow roses with garlic, carrots love
tomatoes”, etc.)This has nothing to do with how a plant actually grows
or behaves in a garden. Science-based companion planting research has
shown that a mixture of varieties of plants is better than mass planting
of one type. It makes it hardier to pest attack, as many pests are
plant-specific. Match plants with similar water and nutrient needs.
Interplanting of tall and short crops so that sun-loving plants can
shelter shade plants makes sense.



Myth#2 Marigolds repel pests.

Data from reputable research shows no such affect. However they do
attract beneficial insects with may feed on pests.



Myth #3 Ants on peonies are necessary to allow the buds to open.

Nope, they are just feeding on the sticky sap produced by the buds. They
do no harm to the flowers but they may attack natural enemies that come
to feed on the nectar and pollen.



Myth#4 Watering on a sunny day will burn plants.

The premise here is that water droplets magnify the sun’s rays and burn
the leaves. Hmmm, let’s see! Do plants burn when the sun comes out
after rain? (There wouldn’t be much left in the tropics then…) Desert
farmers routinely use overhead sprinklers to cool and protect young
plants from drying out. This myth may have come from the observation of
applications of water high in dissolved salts. As the water dries, the
salts left behind can burn the leaves.



Myth#5 Vitamin B1 reduces transplant shock.

This was based on experiments in the 1930’s on detached roots that
indicated a positive affect. Multiple experiments since then on a
variety of plant species in the lab and field, all show no significant
effect of B1 treatment. Researchers from UC Farm Advisory have shown
that B1 supplements, which also containing fertilizer, are no better
than similar fertilizer products, but cost about ten times as much!



Myth#6 Gypsum will “loosen” clay soil, and raise pH.

This is true only if you have soil where sodium, instead of calcium or
magnesium, saturates the clay. In these “sodic” soils gypsum causes soil
particles to gather together, improving structure and water
infiltration. Our foothill clay is typically not “sodic”. Gypsum will
not “loosen” our soil; organic material such as compost is your best bet.

Gypsum’s makeup is calcium sulfate (CaSO4*H2O) and has no effect on pH,
but is a good source of calcium or sulfur.



Myth#7 Pruning seal helps wounds “heal”.

This was based on the premise that a covering of pruning paint or tar
protects the cut surface from decay. In reality: wood-rotting organisms
may already be in the surface, so you are just trapping them in. The
coating can crack leaving the wound even more susceptible to decay. This
coating may also actually inhibit the callus formation on the wound,
slowing the natural protective process. The bottom line - prune at the
proper time for the type of plant, make appropriate pruning cuts, and
let the tree protect itself.



Myth #8 Buy the biggest plants you can afford to get a jump on
growth.

Research has shown that a #1 can oak tree will catch up to (and often
surpass) a #5 can tree within 1 to 2 years. Ohio state research showed
that tomato seedlings that are already fruiting when transplanted yield
poorly, even if the fruits are removed.



Myth #9 If a plant is pot bound, remedy it by cutting the root
ball or teasing roots out and directing downward.

New research from the Univ. of Minnesota shows no difference between
these treatments and no treatment after 2 years.



Here are some final considerations as you evaluate the vast resources of
knowledge:

* Consider the source.
* Does other data support their conclusion?
* If there are only testimonial and no data, or appears to be more
hype than hypothesis, buyer beware!
* And lastly, make sure the data is relevant to your climate, soil,
and ecological conditions. Someone in Connecticut may be able to get by
without watering all summer by using thick mulch, but here in
California, with our dry Mediterranean summers, that probably won’t apply!


Andrew wrote:
On Dec 6, 11:32 am, "Blackadder" wrote:
Do you use the spray during the day?

I used a similar spray and it ended up burning my roses - but it was on
account of the sun's heat. If I had done it in the evening or very early
morning it doesn't happen.

BD


Pyrethrins are also quite oily which probably intensifies the problem
of spraying in hot weather.

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Old 12-12-2007, 09:22 AM posted to aus.gardens
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Posts: 186
Default beware pyrethrum sprays

Fungal spores usually show up in a garden via the wind or insects. One
of the most common are those which cause leaf spot diseases such as
early blight. Tomatoes are highly prone to this type of fungal spore and
can get infected without you even knowing it. Dark brown patches on the
leaves of your tomato plants means they have early blight, which spreads
fast on damp leaves. this is probably mistaken for burnt leaves...

At the first sign of early blight, it is advised to clip off infected
leaves, but only if the foliage is dry. Messing around with damp,
infected foliage will only serve to spread millions of fungal spores
throughout the garden and infect other tomato plants. After infected
foliage is removed (if possible) it is advised to spray down the tomato
plants with a mixture of one part milk to four parts water, along with 1
teaspoon of baking soda for every quart of water used. A few drops of
liquid soap will help to make the spray stick. The reason this spray is
effective is that dried milk when exposed to the Sun's ray's temporarily
changes into a disinfectant, while the bicarbonate component of baking
soda kills new fungal colonies.

Jonno wrote:
Here's a link and part of a theory, which backs up what I read.

http://cahe.nmsu.edu/ces/yard/1999/062899.html

But wait I think there's more...

Jonno wrote:
The water on the leaves story has been around for some time, and been
investigated. The problem is really caused by fungal infections due to
water on the leaves. The sun does not magnify due to different focal
lenght. But plants can suffer from straight out sunburn....Tomatoes
for instance get sunscald.

I'll try and find the story again if I can...

I wonder is some plants are susceptible to the pyrethrum?


Blackadder IIVX wrote:
"Jonno" wrote in message
u...
Maybe you burnt them due to the gas being a sort of refrigerant. In
other words youre spraying a bit too close to the plants.
Do it when there is no winf ie early in the morning when theres very
little wind. Then you can spray them with some distance in between.

Oh no. I use the hand pump manual add ons. I don't use a spray can.

Its just the heat of the sun. Even if you just spray cold water on
the plants- the sun magnifies the droplets and burns the plant.

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Old 13-12-2007, 04:07 AM posted to aus.gardens
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Posts: 276
Default beware pyrethrum sprays

"Blackadder" writes:
Do you use the spray during the day?


Probably about mid-morning on a sunny day.

I used a similar spray and it ended up burning my roses - but it was on
account of the sun's heat. If I had done it in the evening or very early
morning it doesn't happen.


I'll bear that in mind. But I would expect there to have been on the
pack a prominant warning of possible plant damage. I'm surprised that
the matter hasn't been brought up on this group before.
--
John Savage (my news address is not valid for email)


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Old 14-12-2007, 11:10 AM posted to aus.gardens
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Default Some myths regarding gardens or Old Wives tales debunked. myth busters 'R us


"Jonno" wrote in message
...
EXAMPLES OF GARDEN “MYTH”-INFORMATION


...snip 9 items....

Here are some final considerations as you evaluate the vast resources of
knowledge:

* Consider the source.


Of the 9 items none quotes a specific reference and only 3 quote the
institution responsible for the information.

* Does other data support their conclusion?


None of this analysis quotes supporting evidence and most don't even specify
the primary reference.

* If there are only testimonial and no data, or appears to be more
hype than hypothesis, buyer beware!


There's much of this about!

* And lastly, make sure the data is relevant to your climate, soil,
and ecological conditions.


Quite so. Sadly this data, or qualifications relating to it, are also missing
from the quoted cases. The case refering to the use of gypsum refers to "our
foothill clay" as being significantly different but we have no idea where this
is or the nature of such clay.

OTOH there are many myths around in the world of gardening and telling people
to be wary cannot be bad. Some of the cases mentioned probably do have better
information than the myth they are setting out to debunk. Sadly the author
only goes part of the way towards doing what they set out to do.

David


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Old 14-12-2007, 08:50 PM posted to aus.gardens
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Posts: 186
Default Some myths regarding gardens or Old Wives tales debunked. mythbusters 'R us

Yep Youre partly right. Its an item from America, which does have source.
Unfortunately I only wanted to show that the only way to be sure of
things is to check again. I had heard that fungal diseases are spread by
water on leaves, and that the "burning" is caused by other things. At
times we dont stop to think and accept folk lore as factual, due to it
being passed on from father to son etc..
It pays with gardening to find the real facts, and while the internet is
a great source of diversity, it does need to be checked against known
sources of information. This item I believe came from such a source, but
I forget where (Sorry I am also an unknown) We can be pedantic, but I
feel that now our attention has been drawn to this, other can check to
verify, as there are still others spreading the information that water
"burns" leaves. It isnt so! It affects it in other ways. I believe that
the spreading of fungal diseases with wet leaves is much more likely,
and makes more sense....

David Hare-Scott wrote:
"Jonno" wrote in message
...
EXAMPLES OF GARDEN “MYTH”-INFORMATION


..snip 9 items....

Here are some final considerations as you evaluate the vast resources of
knowledge:

* Consider the source.


Of the 9 items none quotes a specific reference and only 3 quote the
institution responsible for the information.

* Does other data support their conclusion?


None of this analysis quotes supporting evidence and most don't even specify
the primary reference.

* If there are only testimonial and no data, or appears to be more
hype than hypothesis, buyer beware!


There's much of this about!

* And lastly, make sure the data is relevant to your climate, soil,
and ecological conditions.


Quite so. Sadly this data, or qualifications relating to it, are also missing
from the quoted cases. The case refering to the use of gypsum refers to "our
foothill clay" as being significantly different but we have no idea where this
is or the nature of such clay.

OTOH there are many myths around in the world of gardening and telling people
to be wary cannot be bad. Some of the cases mentioned probably do have better
information than the myth they are setting out to debunk. Sadly the author
only goes part of the way towards doing what they set out to do.

David




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