too much nitrogen

[steve-o]

a women today who has a very nice lawn that we cut asked about brown spots in it . she has somebody else do the chemicals cause we do not have the proper permits. can too much N cause this or a fungus of some sort. she thinks the co. puts down too much N so they can come back and treat the problem that they caused. i mow and thats it for now so i just stayed clear of this. she is very picky about her yard and it is nice but it is the hardest one we cut. thanks for any help!!!!!!!!

[RRS]

Brown Spot Fungus

Brown Spot Fungus. It's running ramped around here because of the damp hot weather we had in May. Too much N earlier on in the season can make it spread a little worse than normal, but it's everywhere right now. There are fungicides that can be used to treat it.

I don't personally do pesticide applications, but I have a partner/sub that does around 50 or so lawns for me, and we were just discussing how bad the brown spot is this year.

[Seascape]

Environmental conditions that favor disease development in cool-season grasses are day temperatures above 85F and high relative humidity. A minimum daily temperature above 61F in combination with either rainfall or relative humidity above 95% for more than 8 hours are the most critical environmental requirements for disease development. Evening or nighttime thunderstorms from mid-June to late September and a minimum air temperature above 68F are most conducive for severe brown patch. Weather conditions that result in little or no dew formation (i.e., low relative humidity or low soil moisture) or cool nighttime temperatures (i.e., less than 63F) will result in a marked reduction in brown patch severity. Late spring and summer application of nitrogen fertilizers, in particular water soluble nitrogen fertilizers such as urea and ammonium-based products, increase brown patch severity. Evening or nighttime watering or showers will greatly increase disease injury.