Does anyone know if fungicides have to be on the plants for any certain length
of time before it rains? Put another way, do fungicides instantly kill
targetted diseases, or does it take a while? I can't find this info on the
Mancozeb label. Thanks.
Ken

While I don't know much about Mancozeb, anytime I have used fungicides in my
garden, I've always thought it is better to make sure the fungicide has time
to dry on the plant. If you put it on and then it rains an hour later,
well, I don't know how effective it would be. I like to let the stuff dry
and let the plant soak up the stuff, so it has the chance to help the plant.
With the fungicides I've used, they usually call for repeated applications.
Hopefully, someone will recognize and have more specific info for you.
Good-luck.
Darlene

"Ken Anderson" > wrote in message
...
> Does anyone know if fungicides have to be on the plants for any certain
length
> of time before it rains? Put another way, do fungicides instantly kill
> targetted diseases, or does it take a while? I can't find this info on
the
> Mancozeb label. Thanks.
> Ken
>
>

> While I don't know much about Mancozeb, anytime I have used fungicides in my
> garden, I've always thought it is better to make sure the fungicide has time
> to dry on the plant. If you put it on and then it rains an hour later,
> well, I don't know how effective it would be. I like to let the stuff dry
> and let the plant soak up the stuff, so it has the chance to help the plant.
> With the fungicides I've used, they usually call for repeated applications.
> Hopefully, someone will recognize and have more specific info for you.
> Good-luck.
> Darlene
>
>
Thanks Darlene. It looks like the board won't cough up a definitive answer.
I'm using your approach, but I'm getting the willies from all the rain, heat,
and humidity lately. I think that's perfect weather for black-rot.
Ken

You're probably right. We've had tons of rain too, perfect for tomato plant
fungus. Even if it sits on the plants for a couple of hours - it should be
dry, shouldn't it? Different fungicides may be different though. Sometimes
I've had to get stuff on, no matter how rotten the timing, so I wouldn't
wait too long. Have you checked Jack & Lum's sites for any info on
black-rot? Or your county agricultural agent? Good-luck.
Darlene

"Ken Anderson" > wrote in message
...
> > While I don't know much about Mancozeb, anytime I have used fungicides
in my
> > garden, I've always thought it is better to make sure the fungicide has
time
> > to dry on the plant. If you put it on and then it rains an hour later,
> > well, I don't know how effective it would be. I like to let the stuff
dry
> > and let the plant soak up the stuff, so it has the chance to help the
plant.
> > With the fungicides I've used, they usually call for repeated
applications.
> > Hopefully, someone will recognize and have more specific info for you.
> > Good-luck.
> > Darlene
> >
> >
> Thanks Darlene. It looks like the board won't cough up a definitive
answer.
> I'm using your approach, but I'm getting the willies from all the rain,
heat,
> and humidity lately. I think that's perfect weather for black-rot.
> Ken
>
>

Hi Dar V,

(And hello everyone else i'm new!)

Here is a webpage with some info on:

http://extoxnet.orst.edu/pips/mancozeb.htm

It has data about the substances breakdown in soil & in rain about 1/2 way down.

HTH,
Dave

************************************************** ***********
** "Trust me i'm a chemist it'll work - here you light it" **
************************************************** ***********

"Dar V" > wrote in message >...
> You're probably right. We've had tons of rain too, perfect for tomato plant
> fungus. Even if it sits on the plants for a couple of hours - it should be
> dry, shouldn't it? Different fungicides may be different though. Sometimes
> I've had to get stuff on, no matter how rotten the timing, so I wouldn't
> wait too long. Have you checked Jack & Lum's sites for any info on
> black-rot? Or your county agricultural agent? Good-luck.
> Darlene
>
> "Ken Anderson" > wrote in message
> ...
> > > While I don't know much about Mancozeb, anytime I have used fungicides
> in my
> > > garden, I've always thought it is better to make sure the fungicide has
> time
> > > to dry on the plant. If you put it on and then it rains an hour later,
> > > well, I don't know how effective it would be. I like to let the stuff
> dry
> > > and let the plant soak up the stuff, so it has the chance to help the
> plant.
> > > With the fungicides I've used, they usually call for repeated
> applications.
> > > Hopefully, someone will recognize and have more specific info for you.
> > > Good-luck.
> > > Darlene
> > >
> > >
> > Thanks Darlene. It looks like the board won't cough up a definitive
> answer.
> > I'm using your approach, but I'm getting the willies from all the rain,
> heat,
> > and humidity lately. I think that's perfect weather for black-rot.
> > Ken
> >
> >

Most fungicides don't kill existing infection and are mainly applied
as a preventive. Some specific applications are intended for killing
existing spores, but you will have to look around for them. My
understanding is that Mancozeb is a preventive and will not kill an
existing infection.




"Ken Anderson" > wrote in message >...
> Does anyone know if fungicides have to be on the plants for any certain length
> of time before it rains? Put another way, do fungicides instantly kill
> targetted diseases, or does it take a while? I can't find this info on the
> Mancozeb label. Thanks.
> Ken

"Brad B." > wrote in message
>
> My understanding is that Mancozeb is a preventive and will not kill an
> existing infection.
>
>
If that's true, then the Mancozeb needs to be on the plant when and if a spore
lands on it. Once it's washed off, it would have zero effectiveness. Sounds
believeable to me.
Ken

Ken Anderson wrote:

> "Brad B." > wrote in message
>>
>> My understanding is that Mancozeb is a preventive and will not kill an
>> existing infection.
>>
>>
> If that's true, then the Mancozeb needs to be on the plant when and if a
> spore
> lands on it. Once it's washed off, it would have zero effectiveness.
> Sounds believeable to me.
> Ken

I believe Mancozeb - Penncozeb will ramain to some extent after a rain. A
lot depends on the amount of rain and the length of time it rains. I
believe that if the fungicide is on for several hours prior to a rain, some
of it will remain after a light rain. You might just look at the leaves
after a rain and see if there is any spray residue on them. My
understanding also is that Mancozeb - Penncozeb will not kill an existing
infection. You will need a systemic fungicide to do this and they are
expensive. Prevention is the best route.

Mancozeb is a preventative like previously said. A good rule of thumb
is that you will lose 1/2 of the spray for every inch of rain you
recieve. Mancozeb also spreads with rain so sometimes rain can help
coverage. It needs to be dry before the rain and "usually" that calls
for the spray to be on at least 2 hours BEFORE the rain. I also spray
it every 10 days whether it rains or not because of dew. Systemic like
Nova are soaked in to the plant unlike mancozeb/penncozeb/dithane
which lays on top of the leaf. Mancozeb will not kill an infection
like a systemic can it just prevents it from spreading.

Hope this helps.


Bob


"Paul E. Lehmann" > wrote in message >...
> Ken Anderson wrote:
>
> > "Brad B." > wrote in message
> >>
> >> My understanding is that Mancozeb is a preventive and will not kill an
> >> existing infection.
> >>
> >>
> > If that's true, then the Mancozeb needs to be on the plant when and if a
> > spore
> > lands on it. Once it's washed off, it would have zero effectiveness.
> > Sounds believeable to me.
> > Ken
>
> I believe Mancozeb - Penncozeb will ramain to some extent after a rain. A
> lot depends on the amount of rain and the length of time it rains. I
> believe that if the fungicide is on for several hours prior to a rain, some
> of it will remain after a light rain. You might just look at the leaves
> after a rain and see if there is any spray residue on them. My
> understanding also is that Mancozeb - Penncozeb will not kill an existing
> infection. You will need a systemic fungicide to do this and they are
> expensive. Prevention is the best route.