Heat + Rain = Dead Grass

First, let me welcome Lane back;

I hope your sabbatical was productive and recharged your batteries! Second, I would also suggest a corollary to the equation, No Wind + Heat = Dead Grass, and that is: Heat + Rain = Dead Grass.

Another area where stress begins to rear its ugly head is in the area of water management- too much, and not enough.

All too often, we see situations where relative humidity is high, and "hand watering" is done to "cool the plants off". Unfortunately, when RH is high, very little of the water

you put down will evaporate, and this creates the potential for several bad things to happen. As Lane described in his post, fans are incredibly important especially in the Southeast because of the need to reduce the local relative humidity so that the plants can manage the heat.

Fungicide programs are also showing excellent differences, and you can tell the difference between those that perform and those that miss a key disease this year.

To give you an idea of just how we are doing this year, a superintendent in TN sent the following out to his colleagues, and I thought it was interesting:

"Over the weekend I had some fun with numbers. I pulled all my weather records for my course for the past 17 years. I counted the number of 90 degree or above days in the months of June , July and August. Pretty interesting. In 2004 we only had 5 days at or above 90 the whole year. 2006, 2007 we had 40 and 47 days respectively. The highest we had ever had in June was 13 in 1996. The highest ever in July was 28 in 1993. The highest ever in August was 29 in 2007.
1993 must have been a rough year because we has 54 days total, but we were closed, rebuilding our greens that year so it didn't hurt me any.

On average we have had 6.8 days in June at or above 90, 11 days in July and 11.5 days in August.

This year we had 18 days at or above 90 in June and we have already had 18 days in July with a week to go.

The numbers are probably a little different in other areas, but by my measure, that had to be the most stressful June for at least the last 17 years and with the exception of 1993, it looks to be the most stressful July. By far the most stressful two month stretch during that time.

Pass this along to others if you think it will make them feel better. Or just remind them that we are all in the same boat, and that football season is getting closer every day."

It seems to me that golf provides an adequate analogy for taking care of turf under this kind of stress. We have all heard some version of the saying, "The person that misses it the best will win", and I think an appropriate version of that for a summer like this is, "The superintendent who knows how to lose a little turf will carry the day". Like he said, "football season is getting closer every day". Try to stay cool everyone!

NO WIND = DEAD GRASS

I'm back.

For those of you who were hoping that my first post would be on bacterial wilt, I am sorry to disappoint you, but we have more important problems here in the Southeast right now.

Several years ago, I got a call from an angry homeowner who lived in a golf course community. The golf course superintendent had installed a fan adjacent to the green in her back yard. Said fan was preventing her from enjoying her patio, keeping her awake at night, and reducing the value of her property.

She must have been a scientist of some sort, because she asked me if I had a mathematical model that could be used to determine if a fan was necessary. So I broke out my plant physiology, meteorology, and calculus books and after several weeks of analysis, I came up with the following equation:

NO WIND + HEAT = DEAD GRASS

I don't think she liked that answer because I never heard from her again. But this summer is proving my equation to be correct: I have never seen fans make such a huge difference in the survival of creeping bentgrass putting greens as they are this year. Just about everywhere I've visited, the creeping bentgrass being impacted by fans is relatively healthy, whereas the turf furthest away from the fans or on greens without fans is really struggling.

It's been a difficult summer and there's no sign of it getting any easier. But if one positive thing can come out of it, we can use it to demonstrate the benefit of turf fans, fine tune the placement of existing fans, or fight for the money to install additional fans. Don't miss this opportunity!

On the disease side, a number of superintendents in our area are still struggling with Pythium root rot, and some summer patch is also showing up on creeping bentgrass greens. For more information about these diseases, please see the following post from last year.

We have also seen a couple of cases of Rhizoctonia zeae on creeping bentgrass greens. This pathogen induces similar symptoms to brown patch, but is active at higher temperatures and the patches or rings have more of an orange coloration. Most fungicides labeled for brown patch will provide good control of R. zeae, but this pathogen is not sensitive to thiophanate-methyl and is less sensitive to iprodione so you should avoid these products.

brown patch, pythium, and summer stresses

Hot and humid is the big story this week. Waterlogged soils are an issue in some areas, both in sand-based greens and native soils.

We are starting to see lots of typical summer decline. Poa annua is checking out, and algae and hot spots are checking in. In areas where bentgrass has been stressed, it’s showing decline too. June feels too early to be dealing with this stuff, but that is what Mother Nature has dealt us this year. If June is kicking our butts, I'm worried what July and August have in store.

With the overly wet conditions, some guys are wanting to needle tine and topdress to get some air movement in their putting greens. But, it’s so hot, such cultural practices could seriously stress out the turf. We are all hoping for some cooler temps next week in order to sneak in some cultural practices. A dip in nighttime lows would really be beneficial. The lows over the past week have been in the 70’s in most of Kansas (a bit lower in western Kansas where humidity is lower), and soil temps at 4-inches are hovering around 80 degrees. We might get some highs in the upper 80's (gee, maybe I'll need a jacket or I might get chilly...) and lows in the mid-60's early next week. Then, the forecast calls for more scorching.

I had a couple of interesting diagnostic cases this week where turf was declining and, as is typical this time of year, no turf pathogens were to blame. In one situation, a surfactant was applied as part of a tank mix and then not watered in, and this may have led to some phytotoxicity especially in our hot conditions. A big clue was that the practice green WAS watered in, and that one was not showing damage.

In another, some extra N a couple of weeks ago kicked the turf into high gear on one putting green. The green got a little puffy, then got scalped, and now it is having a hard time recovering in these conditions.

The turf shown in the photo below is not happy to be drowning:

Here is this morning in pictures, to further illustrate the conditions

It’s SO humid…

* My camera fogged up when I first took it out of the case at the turfgrass research facility at 7:00 am. No that’s not real fog in the photo, that’s condensation on my camera lens. It took about 5 minutes to "equilibrate" to the outside air.

* The dew was thick to the point of sloshiness:

* I could hear the brown patch mycelium crawling around (well, not quite, but almost…):

* Pythium blight is making its first appearance: (mycelium had been present earlier)