[Stellar P]

I want to put down a blanket app of Celsius before it gets too far into the summer. Soon, the temps will creep well into the high 90s and into 100+. I see some members spraying at temps above 90 degrees and the contradiction with the label is making me indecisive.



Right now my daytime highs are hovering around 92 degrees.



I'm sure I've got a problem arising with Gray Leaf Spot. Nothing full blown, but blades infected here and there.
I've purchased Daconil - Chlorothalonil . . . . . . . . . . 29.6% per TAMU Agrilife Extension: https://plantdiseasehandbook.tamu.e...urf/chemical-controls-for-turfgrass-diseases/

Should I do applications of the fungicide, then apply the Celsius at a later date with increased temps closer to the upper 90s? or Go ahead and apply the Celsius while temps are very close to 90, but with a small disease problem?

Any alternate recommendations?

 

[Ecks from Tex]

Celsius is hands down your best option to spray, and spraying at the low rate would be prudent. But just understand that no matter what you do if you apply Celsius in the next couple months you are going to stress your lawn. So know that going into it. With a low rate, blanket app, your grass should be able to recover within a month or less.

I have St. Aug and am very close to you. In our region, with our grass, it's really tough not to stress the lawn with any herbicide application in the summer. I would apply something to try and correct the fungus first and give it a week or so to improve before applying Celsius - you want grass as healthy as you can get it before you weaken it. It will cut down on dead blades/thatch buildup.

I applied Celsius two weeks ago and my St. Aug is slowly starting to recover.

 

[Stellar P]

Celsius is hands down your best option to spray, and spraying at the low rate would be prudent. But just understand that no matter what you do if you apply Celsius in the next couple months you are going to stress your lawn. So know that going into it. With a low rate, blanket app, your grass should be able to recover within a month or less.

I have St. Aug and am very close to you. In our region, with our grass, it's really tough not to stress the lawn with any herbicide application in the summer. I would apply something to try and correct the fungus first and give it a week or so to improve before applying Celsius - you want grass as healthy as you can get it before you weaken it. It will cut down on dead blades/thatch buildup.

I applied Celsius two weeks ago and my St. Aug is slowly starting to recover.

Thanks for putting my mind to ease. I'll be doing the fungicide app this weekend then the Celsius app 1-2 weeks after.

https://images.homedepot-static.com/catalog/pdfImages/87/87eddec9-d089-486f-b473-29f9b0dfc3b6.pdf

I can't find a dilution rate for the Daconil Fungicide Concentrate which relates to a warm season grass. Page 2 in the above link has recommended dilution rates for veggies, fruits, ornamentals and conifers. Should I go with something in the middle? (1.5 Tablespoons/gallon/1000 sq ft.)?

 

[Jeaux Bleaux]

I'm in southwest Louisiana, with temps about the same. I blanket sprayed the yard with Celsius at a medium rate a few weeks ago. The St Aug yellowed up quite a bit, the Bermuda And the one spot I have of unknown grass (think it's centipede) didn't mind it at all.

 

[Ecks from Tex]

Celsius is hands down your best option to spray, and spraying at the low rate would be prudent. But just understand that no matter what you do if you apply Celsius in the next couple months you are going to stress your lawn. So know that going into it. With a low rate, blanket app, your grass should be able to recover within a month or less.

I have St. Aug and am very close to you. In our region, with our grass, it's really tough not to stress the lawn with any herbicide application in the summer. I would apply something to try and correct the fungus first and give it a week or so to improve before applying Celsius - you want grass as healthy as you can get it before you weaken it. It will cut down on dead blades/thatch buildup.

I applied Celsius two weeks ago and my St. Aug is slowly starting to recover.

Thanks for putting my mind to ease. I'll be doing the fungicide app this weekend then the Celsius app 1-2 weeks after.

https://images.homedepot-static.com/catalog/pdfImages/87/87eddec9-d089-486f-b473-29f9b0dfc3b6.pdf

I can't find a dilution rate for the Daconil Fungicide Concentrate which relates to a warm season grass. Page 2 in the above link has recommended dilution rates for veggies, fruits, ornamentals and conifers. Should I go with something in the middle? (1.5 Tablespoons/gallon/1000 sq ft.)?

That product is apparently not marketed as a turf fungicide. But it has the correct active ingredients so I suspect it could be used as such. I would look online for other products with the same AI marketed as turf fungicide and apply that rate. Otherwise, I'd apply the "unless otherwise directed" rate on pg 8.

If you are concerned, you can easily pick up a fertilome systemic fungicide at ACE for $20. I use a more expensive product called Eagle 20 most of the time but fertilome has a good entry level fungicide.

 

[Ecks from Tex]

I'm in southwest Louisiana, with temps about the same. I blanket sprayed the yard with Celsius at a medium rate a few weeks ago. The St Aug yellowed up quite a bit, the Bermuda And the one spot I have of unknown grass (think it's centipede) didn't mind it at all.

@StellarP this is about what my St Aug looked like after spraying. Going with the low rate can lessen it a little but you should expect this. It will take some time to recover and be slower in the hot summer. I like to mow closer to 3 inches after about 2 weeks after spraying (and bag in all my mows the week after spraying) because it helps push healthy growth and recovery.

 

[Stellar P]

That product is apparently not marketed as a turf fungicide. But it has the correct active ingredients so I suspect it could be used as such. I would look online for other products with the same AI marketed as turf fungicide and apply that rate. Otherwise, I'd apply the "unless otherwise directed" rate on pg 8.

Since the Garden Tech Daconil Fungicide Concentrate is not labeled for turf grass use, I'm going to compare the purchased product's active ingredient with products listed on domyown.com which have the same active ingredient.

Purchased:

Garden Tech Daconil Fungicide Concentrate
AI - Chlorothalonil . . . . . 29.6%
1 Pint container
0.36 lbs. Chlorothalonil per Pint

Compared:

Quali-pro 720 SFT
AI - Chlorothalonil . . . . . 54.0%
2.5 Gallon container
6.0 lbs. Chlorothalonil per Gallon

Agrisel Chlorosel Pro 720 Fungicide
AI - Chlorothalonil . . . . . 54.0%
1 Gallon container
6.0 lbs. Chlorothalonil per Gallon

Prime Source Chlorothalonil 720 Select
AI - Chlorothalonil . . . . . 54.0%
2.5 Gallon container
6.0 lbs. Chlorothalonil per Gallon
​

All of the compared products are labeled for use on turf grass. All of the compared products have equal concentrations and percentage yield of the active ingredient.

Application Rates:

Quali-pro 720 SFT
Low Rate: 2.12 - 3.5 Fl Oz per 1000 Sq Ft.
Application every 10 days max
High Rate: 5.5 Fl Oz per 1000 Sq Ft.
Application every 14 days max

Agrisel Chlorosel Pro 720 Fungicide
2.0 - 3.6 Fl Oz per 1000 Sq Ft.
Application every 14 days max

Prime Source Chlorothalonil 720 Select
2.2 - 5.5 Fl Oz per 1000 Sq Ft.
Application every 14 day max
​

Averate Low Rate - 2.106 Fl Oz per 1000 Sq Ft
Average High Rate - 4.866 Fl Oz per 1000 Sq Ft

I'm going to go for an application rate of 3.0 Fl Oz per 1000 Sq Ft.

Let's break down the mass of active ingredient per Fl Oz.

(6.0 lbs. Chlorothalonil / 1 Gallon liquid)x(1 Gallon / 8 Pints)x(1 Pint / 16 Fl Oz) = ( 0.0468 lbs. / 1 Fl Oz.)

( 0.0468 lbs. ) of Chlorothalonil per Fl Oz.

Since I will be applying 3oz of product per 1000 Sq Ft. - (3.0 Fl Oz x 0.0468 lbs. = 0.1406 lbs. per 1000 Sq Ft.)

Garden Tech Daconil Fungicide Concentrate

(0.36 lbs. Chlorothalonil / 1 Pint liquid)x(1 Pint / 16 Fl Oz) = (.0225 lbs. / 1 Fl Oz.)

( 0.0225 lbs. ) of Chlorothalonil per Fl Oz.

(0.1406 lbs. of Chlorothalonil Needed / 0.0225 lbs) = 6.248 Fl Oz per 1000 Sq Ft

6.248 Fl Oz of Garden Tech Daconil Fungicide Concentrate per 1000 Sq Ft​

I'm in southwest Louisiana, with temps about the same. I blanket sprayed the yard with Celsius at a medium rate a few weeks ago. The St Aug yellowed up quite a bit, the Bermuda And the one spot I have of unknown grass (think it's centipede) didn't mind it at all.

this is about what my St Aug looked like after spraying. Going with the low rate can lessen it a little but you should expect this. It will take some time to recover and be slower in the hot summer. I like to mow closer to 3 inches after about 2 weeks after spraying (and bag in all my mows the week after spraying) because it helps push healthy growth and recovery.

It's going to drive me insane having a stressed lawn for July 4th, but it needs to be done.

 

[Ecks from Tex]

@Stellar P holy crap you just went "beautiful mind" on those calculations. :lol:

The rates look about right to me I say go for it.

And one thing you could do to make it a little better for 4th of July is make sure your grass is getting around the 4-4.25 inch range when you apply the herbicide. Mow 2 days before at that height, then apply Celsius AT THE LOW RATE. Then, continue to mow for the next week at 4 inches and bag the clippings. Finally, in week 2, lower your height of cut to 3-3.25 inches and do it in phases, i.e., mow at 4 on a Tuesday and then mow again at 3.25 on Wednesday (I usually have to side discharge when changing the HOC like that). That should help green you up a little and make the brown spots a little less obvious. Around that same time you can throw down some fertilizer to help boost the growth of new foliage.