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View Full Version : Does high nirtogen REALLY, REALLY cause lawn fungus????


KirbysLawn
06-18-2003, 03:27 AM
I must ask. I have been doing this for right near 8 years and have never faced such a wet spring/summer. I can't help but notice the best looking lawns around are the ones that are OVER FERTILIZED by homeowners.

I have a stable fert program and everyone that converts to my program agrees that they have much better growth control and they mow less often. However many, many of the lawns are just ate up with fungus, mainly leaf spot, brown patch, and a little rust. However the lawns that get 35-...-.... fertilizer or have dog **** all over them look the best, no question!!

Could it be possible that underfertilized lawns promote more fungus problems??

65hoss
06-18-2003, 03:48 AM
The first thing we do when rust arrives on a lawn here is put down a high nitrogen fertilizer. The higher nitrogen helps the grass plant to grow past the fungus quicker. Most of the time that will knock it out without having to apply a fungicide.

KenH
06-18-2003, 06:41 AM
The thinking is, high N, obviously produces alot of new growth, therefore keeping plants tender. Tender plants are more susceptible to disease if the path. is introduced. In a case like rust, the N forces the lawn to outgrow the disease.

GarPA
06-18-2003, 06:42 AM
thats a tough question...I'm seeing more and more articles about the fact that high N any time other than twice in the fall is bad news....weakens the root system because of all the top growth. I hate to put down much N right now becuase next week we're supposed to go into the mod 80"s....thank goodness. But on the other hand Hoss is right about high N to help the plant grow out of the fungus....fungus is a real pain and this year its everywhere. Personally I'm trying to let it grow itself out of the fungus assuming its not destroying the entire turf..what a year...I did use granular Ironite for the first time on my own yard a few weeks ago....its low in N and my yard is darker green than my neighbors and its holding that darker color weeks later. Its s bit pricey though.

Strawbridge Lawn
06-18-2003, 06:53 AM
Watch out for those turf nazi's trying to protect the envirnment.
Overfertilization.oohhhh...I guess we could just have them inspect lawn doctor or chemlawn first. hee hee

SWD
06-18-2003, 06:58 AM
The diseases you mentioned are all different causal agents. Nitrogen and the amount of it plays a big part in the disease cycle for these respective, yet different diseases.
On a root borne disease such as Rhizoctonia, adding N is the reason the disease becomes worse.
Rusts are pretty much saphrophitic, so a high N dose is necessary to promote the leaf growth to outgrow the infestation.
Causal agents for leaf spot are a bit different as different causal agents factor into currative measures.
I have read in your previous posts about using Primo Maxx - now this will certainly increase your disease cycles.
Species of turfgrass, the edaphic environment, host environment, cultural inputs, all have an interelating relationship as to pathogen balance that is maintained.
You may have been showing good results for your environment for the last 8 years, however, have you had a spring like this before while using your stable program?
Remember, the disease pathogens are always present. Check again what you are doing, something is not aiding the turfgrass for the environment your are currently in.
Good luck, Steve.

battags
06-18-2003, 08:22 AM
I agree with what everyone else has said but think they are missing the most likely possibility. You guys have had a lot of rain your way, just like us. All of this rain has saturated the soil and can easily leach N, P, K, (and many lessor important nutrients) below root level. Additional N should be used in this case to "green up" a lawn, but P and K can't be overlooked either. Root growth, rhiozome growth, and the grasses ability to withstand dought depend on those nutrients now instead of late summer when it's too late.

battags
06-18-2003, 08:22 AM
I agree with what everyone else has said but think they are missing the most likely possibility. You guys have had a lot of rain your way, just like us. All of this rain has saturated the soil and can easily leach N, P, K, (and many lessor important nutrients) below root level. Additional N should be used in this case to "green up" a lawn, but P and K can't be overlooked either. Root growth, rhiozome growth, and the grasses ability to withstand dought depend on those nutrients now instead of late summer when it's too late.

battags
06-18-2003, 08:24 AM
I agree with what everyone else has said but think they are missing the most likely possibility. You guys have had a lot of rain your way, just like us. All of this rain has saturated the soil and can easily leach N, P, K, (and many lessor important nutrients) below root level. Additional N should be used in this case to "green up" a lawn, but P and K can't be overlooked either. Root growth, rhizome growth, and the grasses ability to withstand drought depend on those nutrients now instead of late summer when it's too late.

battags
06-18-2003, 08:26 AM
Sorry guys, my computer was acting up and I posted that 3 times accidentally. Woops!

CMerLand
06-18-2003, 09:13 AM
Its all in the balancing act of how much and what type of fertilizer your putting down. Certain diseases will attack turf grown under lower fertility such as dollar spot, rust and red thread, although all may also show up on properly fertilized turf as well. The addtional fert helps mask the symptoms of these disease by stimulating growth.

Other diseases attack turf under high fertility such as brown patch which can be much more damaging and spread faster. Weather conditions, watering habits thatch levels and clipping removal are all also significant factors in turf disease development and spread.

As far as your comment regarding the 35-x-x, whenever I hear someone spout off numbers like that it tells me they dont have a clue. Those numbers are absolutely meaningless without knowing the rate of application. All these numbers mean are the percentages of that fert in that bag. Two 50 lb bags of fertilizer one 35-x-x and one 10-x-x will put down the same 1lb of N per 1,000 sq feet the only difference is that the first bag will cover 17,500 sq and the second will cover only 5,000. So youll need alot more bags to cover an acre if your looking to put down that same 1lb per 1000.

Grassmechanic
06-18-2003, 03:32 PM
Originally posted by SWD
The diseases you mentioned are all different causal agents. Nitrogen and the amount of it plays a big part in the disease cycle for these respective, yet different diseases.
On a root borne disease such as Rhizoctonia, adding N is the reason the disease becomes worse.
Rusts are pretty much saphrophitic, so a high N dose is necessary to promote the leaf growth to outgrow the infestation.
Causal agents for leaf spot are a bit different as different causal agents factor into currative measures.
I have read in your previous posts about using Primo Maxx - now this will certainly increase your disease cycles.
Species of turfgrass, the edaphic environment, host environment, cultural inputs, all have an interelating relationship as to pathogen balance that is maintained.
You may have been showing good results for your environment for the last 8 years, however, have you had a spring like this before while using your stable program?
Remember, the disease pathogens are always present. Check again what you are doing, something is not aiding the turfgrass for the environment your are currently in.
Good luck, Steve.
SWD, you are right on the money.

Mike

KirbysLawn
06-18-2003, 05:27 PM
Originally posted by CMerLand
As far as your comment regarding the 35-x-x, whenever I hear someone spout off numbers like that it tells me they dont have a clue. Those numbers are absolutely meaningless without knowing the rate of application.

I posted that representing the hign N amounts Home Depot & Lowes sells, didn't feel I needed to list all the different types (29-3-4, 30-3-3, 36-5-10.....) do I? I also have no idea what rates thay are apply but since many are mowing 3 -4 times a week I would make the assumption they are getting too much N, is this correct?

The findings noted in past post are representive of all lawns, Prioo Max treated or not; maintained by me or not. Seems the lawns that look the best, the ones who have little or no fungus are the ones mentioned above...I find it interesting.

Nick
06-18-2003, 08:43 PM
I feel the water is washing over diluting the Nitrogen. I find that lesco polyvex with it's very graduale realease is giving a better cplor then the poly plus. Try a few bags.

AltaLawnCare
06-18-2003, 09:25 PM
The exten office here put ou an article stating that the excessive rain was leaching out the Nitrogen in the soil. And that ."..lawns fertilized heavily last fall are the strongest most disease free now.."

KirbysLawn
06-19-2003, 02:40 PM
This week I have been putting 18-2-18 25% organic at half rates to improve the color...It's still raining so I may get it finished soon. :mad: