Disease Control / Daconil / Rain questions

tam91 · June 24, 2011

How do you manage disease control when it rains what seems like every 10 minutes? Seriously, it's raining every or at least every other day, at least a bit.

I don't have the Daconil brand, but what I have is Chlorothalonil (same active ingredient). It says to spray once a week, but only so many times per season (far less than the number of weeks remaining).

When it rains constantly, does one just ignore that max times, and apply it each time it rains? Or....?

Lastly, I can't remember - does the Daconil need to get on the underside of the leaves (as much as possible) or do most of the fungi attach on the top?

**carolyn137** · June 24, 2011

Quote:

Originally Posted by tam91

How do you manage disease control when it rains what seems like every 10 minutes? Seriously, it's raining every or at least every other day, at least a bit.

I don't have the Daconil brand, but what I have is Chlorothalonil (same active ingredient). It says to spray once a week, but only so many times per season (far less than the number of weeks remaining).

When it rains constantly, does one just ignore that max times, and apply it each time it rains? Or....?

Lastly, I can't remember - does the Daconil need to get on the underside of the leaves (as much as possible) or do most of the fungi attach on the top?

Tam, daconil is just a trade name and there are many brands. Right now there's a Cornell Late Blight alert and I have Bonide Fung-o nil, which is daconil and the chemical name of daconil, the active ingredient, is chlorothalonil.

Most folks ignore the 6X a season and that was just discussed in another thread here as far as I remember.

You're using Daconil to help prevent fungal foliage diseases of which Early Blight and Septoria leaf spot are the two most common. They have specific attachment sites on TOP of the leaf and what Daconil does is to block those sites so those pathogens can't attach and initiate infection.

What to do about rain. it's been raining constantly here and with the LAte BLight alert I really want Freda to spray but what's the use if it gets washed off after every heavy rain. So she's been picking off any yellow leaves, any with spots, I see some Early Blight ( A. solani) and we'll look for a few days in a row with little to no predicted rain to spray, the other problem being she can't just drive here when the sun is out to spray.

Mudman · June 24, 2011

Quote:

Originally Posted by carolyn137

You're using Daconil to help prevent fungal foliage diseases of which Early Blight and Septoria leaf spot are the two most common. They have specific attachment sites on TOP of the leaf and what Daconil does is to block those sites so those pathogens can't attach and initiate infection.
.

I have read many post with people recommending to spray the entire plants but just to clarify Carolyn, it is only necessary to spray the top of leaves?

**carolyn137** · June 24, 2011

Quote:

Originally Posted by Mudman

I have read many post with people recommending to spray the entire plants but just to clarify Carolyn, it is only necessary to spray the top of leaves?

Correct, just the top if speaking of the fungal foliar pathogens.

They're spread by air and embedded in rain drops so fall on top of the foliage.

There's also splashback reinfection where spores can fall to the gound from infected plants, overwinter and then the next season be splashed back to the lower foliage and initiate infection. many folks remove that lower foliage, many folks mulch their tomato plants so splashback isn't a problem and some like me, who grows tomatoes by sprawling, or did until she got put in this walker, just try to spray as best they can.

The prevalence of those kinds of Foliar fungal pathogens in a specific area can vary considerably from year to year.

And we're talking FUNGAL foliar pathgens here b'c Daconil has no activity at all against the bacterial foliage pathogens. Which is why it's so important to know what kind of infection (S) you might expect so that you can spray to help prevent them.Daconil can't cure an infection but can help prevent infections and as is true in almostof Biology, it's not 100% effective, but darn close if a proper schedule can be maintained, which is darn difficult as this thread has illustrated.

tam91 · June 24, 2011

Sun? What's sun? I think I have forgotten, I haven't seen it in so long.

Thanks Carolyn, that's pretty much what I figured. I'll just spray when I can.

Talon1189 · June 24, 2011

I have had similar rainy weather where I live. It has been about 10 days since I sprayed any Daconil on my plants. Tomorrow (Saturday) it is going to be sunny so my plants will get a dousing of the fungicide. I would spray once a week is the weather would allow my to

>>>>>Talon

JerryL · June 24, 2011

It had been awhile since I sprayed so I went out this morning. The sun was shining and I had high hopes. I clipped off all the yellow foliage and got out the Daconil. When I finished spraying I came inside to eat lunch. As soon as I sat down with my ham and swiss on rye the skies darkened and the rain began to fall.

Oh well. What are you going to do?

The forecast says rain everyday until next Wed thru Fri. Maybe I’ll try again then.

Mudman · June 24, 2011

Thanks for the clarification. Septoria last year. This year is the first year I've sprayed anything. So far so good. I have always mulched and removed lower leaves so hopefully the addition of the spraying will keep the septoria at bay.

b54red · June 25, 2011

Well the long drought seems to be temporarily over because we have been getting summer thunderstorms a couple of times over the past week and a half and spraying is a real pain. Seems every time they say no rain and I spray then later the same day or the next I get a good shower which washes the Daconil off. Some foliar diseases are starting to pop up and I fear a return of gray mold which was devastating earlier this year so I will start spraying with my bleach again. It is cheap and is only useful on diseases already present with no residual preventative effectiveness except for its' value in getting rid of something before it spreads. I had to spray twice a week for nearly a month and a half two years ago because of almost daily rain. It worked well in controlling the diseases which were destroying some of my friends tomato gardens while mine kept right on producing. Now they also use the bleach spray in rainy conditions or to slow down a disease that has taken hold.

Aphid · June 25, 2011

Mr B54Red, do you have a ratio on the bleach spray and how often? I have a couple plants that could possibly benefit from this regimen

lurley · June 29, 2011

Can I use Spectracide Immunox Fungicide on tomatoes? It says it does not get washed off by rain. I have been cutting off the leaves of my tomato plants that have early blight from all this rain as I finally have a few dry days to get them in the ground. They look like green sticks with just a few leaves at the growing tip. I'm hoping removing all the diseased foliage and spraying with fungicide will help.

**carolyn137** · June 29, 2011

Quote:

Originally Posted by lurley

Can I use Spectracide Immunox Fungicide on tomatoes? It says it does not get washed off by rain. I have been cutting off the leaves of my tomato plants that have early blight from all this rain as I finally have a few dry days to get them in the ground. They look like green sticks with just a few leaves at the growing tip. I'm hoping removing all the diseased foliage and spraying with fungicide will help.

http://www.spectracide.com/Products-....aspx?iframe=1

No, can't use it on tomatoes per the above link.

bcday · June 29, 2011

The reason Spectracide Immunox won't wash off in the rain is that it is systemic, meaning that it is absorbed into the plant tissues and distributed upward by the plant's vascular system into all the parts of the plant, including into the fruit.

In other words, you're going to be eating this stuff. It's true that it won't wash off in the rain once it dries because it will be working from inside the plant. But you also can't wash it off the fruit because it's in the fruit, not on it.

It isn't really something I'd want to use on my homegrown tomatoes. On the other hand, if it's legal for farmers to use it on tomatoes then you may be eating it in any tomato products you buy in the grocery store anyway.

Chlorothalonil is not systemic. It doesn't get circulated within the plant. It will eventually wash off in rain and you can also wash it off the fruit.

June 24, 2011	#1
tam91 Tomatovillian™ Join Date: Aug 2010 Location: Crystal Lake IL Posts: 2,484	Disease Control / Daconil / Rain questions How do you manage disease control when it rains what seems like every 10 minutes? Seriously, it's raining every or at least every other day, at least a bit. I don't have the Daconil brand, but what I have is Chlorothalonil (same active ingredient). It says to spray once a week, but only so many times per season (far less than the number of weeks remaining). When it rains constantly, does one just ignore that max times, and apply it each time it rains? Or....? Lastly, I can't remember - does the Daconil need to get on the underside of the leaves (as much as possible) or do most of the fungi attach on the top? __________________ Tracy

June 24, 2011	#5
tam91 Tomatovillian™ Join Date: Aug 2010 Location: Crystal Lake IL Posts: 2,484	Sun? What's sun? I think I have forgotten, I haven't seen it in so long. Thanks Carolyn, that's pretty much what I figured. I'll just spray when I can. __________________ Tracy

June 24, 2011	#6
Talon1189 Tomatovillian™ Join Date: Apr 2010 Location: Farmington, Michigan. Zone 5b/6a Posts: 421	I have had similar rainy weather where I live. It has been about 10 days since I sprayed any Daconil on my plants. Tomorrow (Saturday) it is going to be sunny so my plants will get a dousing of the fungicide. I would spray once a week is the weather would allow my to >>>>>Talon __________________ Always looking for a better way to grow tomatoes ..........

June 24, 2011	#7
JerryL Tomatovillian™ Join Date: Feb 2006 Location: S.W. Ohio z6a Posts: 736	It had been awhile since I sprayed so I went out this morning. The sun was shining and I had high hopes. I clipped off all the yellow foliage and got out the Daconil. When I finished spraying I came inside to eat lunch. As soon as I sat down with my ham and swiss on rye the skies darkened and the rain began to fall. Oh well. What are you going to do? The forecast says rain everyday until next Wed thru Fri. Maybe I’ll try again then. __________________ Jerry

June 24, 2011	#8
Mudman Tomatovillian™ Join Date: Apr 2011 Location: NW Wisconsin Posts: 910	Thanks for the clarification. Septoria last year. This year is the first year I've sprayed anything. So far so good. I have always mulched and removed lower leaves so hopefully the addition of the spraying will keep the septoria at bay. __________________ Mike

June 25, 2011	#9
b54red Tomatovillian™ Join Date: Sep 2009 Location: Alabama Posts: 7,068	Well the long drought seems to be temporarily over because we have been getting summer thunderstorms a couple of times over the past week and a half and spraying is a real pain. Seems every time they say no rain and I spray then later the same day or the next I get a good shower which washes the Daconil off. Some foliar diseases are starting to pop up and I fear a return of gray mold which was devastating earlier this year so I will start spraying with my bleach again. It is cheap and is only useful on diseases already present with no residual preventative effectiveness except for its' value in getting rid of something before it spreads. I had to spray twice a week for nearly a month and a half two years ago because of almost daily rain. It worked well in controlling the diseases which were destroying some of my friends tomato gardens while mine kept right on producing. Now they also use the bleach spray in rainy conditions or to slow down a disease that has taken hold.

June 25, 2011	#10
Aphid Tomatovillian™ Join Date: Jun 2008 Location: Nashville TN zone 6-B Posts: 133	Mr B54Red, do you have a ratio on the bleach spray and how often? I have a couple plants that could possibly benefit from this regimen

June 29, 2011	#11
lurley Tomatovillian™ Join Date: Jan 2011 Location: Central Ohio Posts: 741	Can I use Spectracide Immunox Fungicide on tomatoes? It says it does not get washed off by rain. I have been cutting off the leaves of my tomato plants that have early blight from all this rain as I finally have a few dry days to get them in the ground. They look like green sticks with just a few leaves at the growing tip. I'm hoping removing all the diseased foliage and spraying with fungicide will help.

June 29, 2011	#13
bcday Tomatovillian™ Join Date: Jan 2006 Location: NY z5 Posts: 1,205	The reason Spectracide Immunox won't wash off in the rain is that it is systemic, meaning that it is absorbed into the plant tissues and distributed upward by the plant's vascular system into all the parts of the plant, including into the fruit. In other words, you're going to be eating this stuff. It's true that it won't wash off in the rain once it dries because it will be working from inside the plant. But you also can't wash it off the fruit because it's in the fruit, not on it. It isn't really something I'd want to use on my homegrown tomatoes. On the other hand, if it's legal for farmers to use it on tomatoes then you may be eating it in any tomato products you buy in the grocery store anyway. Chlorothalonil is not systemic. It doesn't get circulated within the plant. It will eventually wash off in rain and you can also wash it off the fruit.