So much depends on the weather

So much depends on the weather

Features - Weed/Disease/Insect Control

Five turf experts weigh in on the biggest disease threats across the country, and what LCOs can do this fall to help grass rebound.

September 17, 2012
Chuck Bowen
Industry News

Sam Wineinger
Territory sales manager, midwest Arysta LifeScience

From a disease standpoint, the pressure’s been easier this year. Having to control diseases is a good thing because you have grass.

Without irrigation, there hasn’t been a lot of disease due to the drought. The grass has gone dormant, there’s been very little as far as treatment goes on un-irrigated turf. If it’s irrigated, we’ve seen brown patch, pythiums; summer patch has started to show symptoms in the Upper Midwest. The normal suspects have been present in irrigated turf. Non-irrigated turf has just struggled to stay alive.

In my region this fall, as they get into the time when they’re going to be doing renovations and overseeding, if the temps hang on, the patch diseases and dollar spots will continue to be prevalent, especially with the soil temps as warm as they are, and the water and the fertilizer that’s going to be required to establish these areas to reestablish the turf that has gone dormant over the summer. Preventative treatments for brown patch, pythium and dollar spot are still going to be required.

We do see some fungicide use through the summer in the mountain states and up into the northwest for necrotic ring spot. That’s still persisted. It’s dry there, too, but hasn’t been as prevalent as is probably normal.

Everything’s been so dry and warm, it’s really thrown the disease cycle for a loop this summer. You just haven’t had that overnight humidity to hold that disease gradient in check in the Midwest. The plants dry off so fast, the dew doesn’t set and hold. I think the take-home message is Mother Nature has been the best fungicide of the year. Ninety-five degrees and no humidity is one of the best fungicides you can have.

Jimmy Johnson
Fungicide product manager, Bayer CropScience

The biggest thing this year early on as the season progressed, it seemed like we were getting hit with a lot of dollar spot along the East Coast, then the heat came on, and we had some periods where brown patch was really heavy.

Now it depends on your situation with water. In the Midwest and those areas that are critically dry, so you’ve got a lot of brown lawns, you’ve still got a lot of areas that are seeing some brown patch pressure, and they’re getting other stress areas on bluegrass –seeing some summer patch.

It’s been a challenging year, depending on the area that you’re in. There can be cases where they gave up worrying about disease and are looking at the fall as an opportunity for fall seeding. That’s going to be one of the major focuses for the fall is renovation.

The biggest things, and again it all depends on the weather, if we go into the fall warm and we’ve got moisture, I think they might want to be concerned with protecting their seedlings from pythium and phytopera during germination. The biggest thing should be, after that, as we cool off and get some moisture, some areas might experience some dollar spot. The biggest things if they are renovating that they protect those seedlings and get a good stand established.

Kyle Miller
Senior technical specialist, BASF turf and ornamental products

In a nutshell, a few diseases have been most prevalent this year. In the spring, red thread was a real, real problem. For a lot of people they never got rid of it. Usually a little fertilizer will help turf grow out of it. We’ve also seen a fair amount of dollar spot, and that’s usually a golf course problem, but there’s been a lot in home lawns and commercial lawns.

Brown patch and pythium, the warm weather diseases, hit recently. For a while, those 100-degree temperatures were almost too hot for brown patch. It was hot and dry and we weren’t really seeing it. Pythium is a hot weather disease. It can hit one day and a day or two it can wipe out turfgrass.

Residential properties, they tell you after the fact. The way to have controlled it was to have prevented it. It’s educating consumers about when diseases occur. A lot of people think it’s the heat or drought that’s killing their grass, but it’s brown patch that’s causing the turf to wither away.

The only way you’re going to maintain a healthy lawn in this part of the country is to have treated before. Here’s the deal: Pay me now or pay me later. If you’re going to let your turf die, you’re going to need to have it reseeded in the fall. You can pay me whenever you want.

We do run into higher-end customers who have irrigation. Irrigation is moisture, and moisture is what diseases need to really grow.

I have a feeling we have a lot of dead, dead grass. This fall LCOs are going to be doing a lot of reseeding and overseeding lawns. The damage is done to the turf already. Unless we get some good soil moisture back, some of it will recover, but a lot of it may not.

Bruce Clarke
Extension specialist and professor of turfgrass pathology, Rutgers University

Overall the major landscape diseases this year included red thread in the spring. It came in very early, in early April, and persisted into late June. Dollar spot pressure was very high in June in the New Jersey area. I also saw a surprisingly high level of rust on Kentucky bluegrass this summer. It started in June and did not decline in severity until early July.

In general, we are suggesting getting back to basics (proper fertility, irrigation) to improve plant vigor for all three of these stress-related diseases. Also, scouting landscapes for outbreaks and applying fungicides on high value areas, especially those with a prior history of disease, with fungicides known to be effective for the disease in question.

You can only go so far in suppressing diseases with cultural controls, so on high-value areas, fungicides are sometimes required. In those cases, the key is not to let the disease get out of control or the turf will lose a lot of density and open the area up to weeds and other problems.

Summer patch has also been a big problem due to the very hot summer, particularly in poorly drained, compacted sites with high soil pH. Also brown patch was very prevalent during hot, humid weather on landscapes that received a lot of rain from localized thunder storms.

With the warm winter and hot summer in 2012, I think you can exact a lot of rust again this fall as well as dollar spot.

Lane Tredway

Technical manager for the southeastern U.S. / Syngenta

This year got off to a good start for a couple reasons. Temps were high in the spring, warm season grasses got off to a good start. That helped us to avoid problems with large patch, which is very common on warm season grasses like zoysiagrass, St. Augustine and centipede grass, and which hits in spring and fall when the turf is growing slowly.

Cool season grasses – tall fescues, Kentucky bluegrass – had a pretty good year as well, until we got the humidity and rain in some areas that lead to brown patch and pythiums.

Diseases are very simple organisms – they’re just sitting there in the thatch and when temperature and moisture conditions become ripe, they can develop very quickly and cause a problem seemingly overnight. The pathogens are always there; there’s nothing we can do to eradicate them. There are things from a management standpoint to make the turf more resistant – basic stuff like proper fertilization, mowing at the proper height, not overwatering.

The fall all depends on what Mother Nature decides to bring. It’s almost impossible to predict really. If we have a cool and wet fall, we’ll get large patch. If it stays warm and relatively dry, we’ll have fewer problems.

The key for LCOs is the selection of a good grass. There are new varieties of tall fescue that has good quality. Check with your local extension services to make sure you’ve got the best variety for your climate.