View Full Version : Losing my kentucky bluegrass to disease.

07-25-2011, 02:19 PM
I live in NJ and the temps here have been in the high 80-90's with constant humidity for a few weeks....My lawn (sod) is going on its 4th year. I applied eagle20ew fungicide. Its amazing how in the course of only a few weeks its gotten such bad spots...I applied Lesco Allectus around when it got worse only to find that nitrogen helps alot of disease...some spots have white spots all over the blades others have a frog eye appearance...My watering has been 2-3 times per week...6 zones 40 mins each zone starting @ 3am....I know bluegrass fixes itself in some spots im just curious if anyone has any advice...my lawn normally stays perfect and now it just looks like crap in alot of spots...I made the mistake of forgetting to aerate last fall so i have some compacted spots..i will also dethacht in september....soil test was good but PH was law I applied cal turf pro to get PH back in check....any help is apprecaite thanks

07-25-2011, 05:31 PM
Blindly putting a fungicide down without knowing exactly what pathogen you are dealing with doesn't help much. Can you take several photos and post them on here? Once we know what you have we could make some recommendations from there.

For now, I would ease off on your irrigation schedule to maybe once per week. Many spot type diseases are brought on by excessive moisture and humid conditions.

07-25-2011, 09:21 PM
In NE OHIO we have had temps in the high 90's and high humidity but that isn't as important as the high overnight temps and humidity. I have seen some juicy Rizoc on Bluegrass because of the atmospheric conditions of the past few days. Especially after the rain we had over the weekend. Call it meltdown!

Be very careful watering and if it's humid only water if you absolutely have too and do it in the morning after the sun has come up. Wet grass, humidity and high nighttime temps= petri dish on steroids.

07-26-2011, 12:24 AM
You cannot cut back on water--its too hot. Grass dries out too quick. High humidity and high night temperatures really stimulate the fungus diseases. Perhaps switch to day watering so that the grass is never wet more than an hour at a time--too quick for fungus to spread.
Jojo is right; you have to have a good disease diagnosis before you can treat it. You mentioned white spots: could be powdery mildew, (common in shade). You mentioned frog-eye spots--could be necrotic ring spot, (common in sunny sod).
Allectus is for insects.

07-26-2011, 10:48 AM
The problem with watering in this heat is that if your water sits very long on top and actually evaporates from the surface rather than soak in, you are going to experience fungus and drought symptoms... Most of what I see around the neighborhood isn't fungus at all; it is mowing too short, too often...

Fletcher Reede
07-26-2011, 11:19 PM

Hissing Cobra
07-27-2011, 12:46 AM
It sounds like you have Necrotic Ring Spot. It attacks the roots and kills them off. It's also very common in sodded Bluegrass Lawns but can attack other species as well. Do some research on it and come up with a plan of attack to help things out.

You'll have to incorporate fungicides into your program, which is going to raise your yearly pricing for the lawn products. Also, you'll have to aerate your lawn at least once per season (two or three times will be better if you can do that). Incorporating Organic fertilizers during the summertime will increase microorganism activity which will help out as well. This is not an easy disease to deal with at all. Good luck.

07-27-2011, 06:19 PM
Sounds like powdery mildew and a patch disease, partially encouraged by your recent fertilization and definitely helped by watering at 3am. Can you start a couple hours later to minimize the amount of time the turf is wet at night? Also, is there too much shade, or not enough airflow, in the areas where you're getting fungus? Kentucky Bluegrass is great, but not in shade. Might need to do some tree pruning? Again, it's hard to diagnose a fungus without pics.

08-01-2011, 09:57 PM
Guys thanks for the input....the lawn was absolutely perfect until around 4th of july...temps in NJ were constantly humid the entire month with only raining once or twice....I water starting @ 3am because it starts getting light at 5:30....I have used eagle 20ew a few times, my local lesco dealer has said the disease is Athracnose. I have reduced watering as much as I can....


08-02-2011, 02:10 PM

08-02-2011, 02:35 PM
You are looking at applying Eagle, then 3336, then Heritage or Insignia on a 14 day rotation. Do not stop watering. You need to supply 1" plus of water per week. If it is humid, then the idea of not watering when the sun is out is malarkey. It is too humid for the water to evaporate. You might also be looking at a short irrigation cycle during the day to try to keep the grass cool. I know I am in a different region, but in the 1990's something similar happened to all of the bermuda lawns here. Similar weather conditions, hot and humid, but no rain. Back then, the toxic contact fungicides were allowed on residential lawns, so I was alternating between Daconil+3336, Fore+Bayleton and Chipco 26019.

Another thing to consider is a high potassium, high micronutrient, moderate nitrogen fertilization program. When a lawn has suspected necrotic ring spot or Take All Patch, I do not want any urea nitrogen on the grass. It is to be ammonium sulfate.

08-02-2011, 04:28 PM
perhaps you actually have mostly perennial ryegrass. It looks the same as Kentucky bluegrass, but if a mixture was planted, it may predominate after a few years.
In that case I would suspect brown patch fungal disease, (considering the hot humid conditions.).

Keep the fungicide coming. Heritage is better for brown patch. See U of Maryland data.