Renown: Broad Spectrum Activity via Azoxystrobin and Chlorothalonil

Ha! Megan was right. Sorry for not posting this on Thanksgiving day as per the schedule, but Wong Family Thanksgiving in Fresno is serious business and I was definitely passed out in a food coma by mid-afternoon. Soo....here's a Sunday post to make up for it.

Renown Fungicide - Broad Spectrum Control of Foliar Diseases
Renown is a fungicide pre-mix recently labeled by Syngenta for use in the U.S. The active ingredients in Renown are azoxystrobin and chlorothalonil, which are the active ingredients in Heritage and Daconil fungicides respectively. When it comes to broad spectrum activity, you can't get much broader spectrum than both of these two active ingredients. Azoxystrobin is a QoI that is effective against a number of ascomycete, basidiomycete and oomycete pathogens. Chlorothalonil, as you all know, pretty much takes care of most foliar pathogens (including algae) but not foliar Pythiums.

Renown has a wide range of activity against a number of diseases including: algae, anthracnose, brown patch, copper spot, dollar spot, gray leaf spot, large patch, stem rust, stripe rust, southern blight, yellow patch, yellow spot, zoysia patch, leaf rust, leaf & sheath spot, melting out, Microdochium patch, pink patch, powdery mildew and red thread.

Because azoxystrobin is a systemic fungicide while chlorothalonil is a contact, the best use of Renown would be for foliar disease control. Also, if the product is applied in 2 gal water per thousand, that should also be enough to cover diseases that reside in the thatch, mat or upper root zone on closely mowed turf types (i.e. grees and tees). When targeting deep soil and root infecting pathogens like fairy rings, it may be better to use a different fungicide this purpose. Watering-in a Renown application to get soil activity from the azoxystrobin component could cause you to lose the benefit of the chlorothalonil for foliar disease control.

Renown comes as a suspo-emulsion formulation containing 0.32 lbs of azoxystrobin and 4.84 lbs of chlorothalonil per gallon. Use rates are 2.5 to 4.5 fl oz which is equivalent to 1 fl oz Heritage TL plus 2 fl oz Daconil Weatherstik and 1.8 fl oz Heritage TL plus 3.6 fl oz Daconil Weatherstik, respectively.

Renown has looked very good in our anthracnose and pretty good for dollar spot as you can see in the next few slides.





Two applications of Renown also appeared to be effective in controlling brown ring patch in 2008 trials in San Diego: archive.lib.msu.edu/tic/gcman/article/2009aug74.pdf

The benefit for using Renown would be in the control of multiple diseases where the combination of azoxystrobin and chlorothalonil would put you at a distinct advantage. For example, when leaf spots and brown patch are active at the same time, or gray leaf spot and Southern Blight, etc. There are some specific situations where using Renown would also make sense as described below.

Fungicide resistance. For certain diseases like anthracnose and gray leaf spot, where QoI-resistance is a problem, the pre-mix would be of an advantage. For both of these diseases, QoI-resistance has been a problem in a lot of locations, but the addition of chlorothalonil in the application would help control those resistant isolates. For other diseases, where QoI-resistance is not yet a problem, the mixture would aid in helping to delay resistance due to the dual mode of action.

Dollar spot. Although the WG formulation of Heritage is not particularly effective vs. dollar spot, it appears that the liquid TL formulation has better activity against the disease. The additional of chlorothalonil would help in controlling the disease. This would be valuable when there are other diseases like brown patch are active.

Non-DMI for summer disease control. Renown can pick up a lot of the mid- & late-summer diseases you would face on cool season and warm season turf like leaf & sheath spot, melting out, anthracnose, etc. Although highly effective, there can be times in the summer when a non-DMI would be advantageous for use in these situations.

Keep in mind that applications of Renown count towards the yearly limit of chlorothalonil use on turf. Each application contains 1.5 to 2.7 oz chlorothalonil, and recall that there is a 9.5 oz, 19.1 and 26.8 oz chlorothalonil per 1,000 sq ft yearly limit for roughs& fairways, tees, and greens, respectively.

Damn it's Cold on the West Coast
Although we're still a few weeks away from the official start of winter, it's been pretty damn cold in the West. Seattle got snow last week and Portland was pretty much frozen last Tuesday and Wednesday. Temps in the 50s-60s are present in much of the Golden State with below freezing night time temps being seen in the Central Valley.

Pink snow mold is likely to be coming in these cold wet conditions and so is freeze and winter damage.

Other than that, I hope everyone had a great Thanksgiving holiday! I'll see some of you in Portland this Thursday at the Oregon Pesticide Seminar.

Until then, signing off from the Right Coast....

Large patch is brewing in the warm-season grasses

With cool, wet weather setting in across much of the southeast, now is the time to initiate a preventive fungicide program for large patch on the warm-season grasses. Zoysiagrass, centipedegrass, and St. Augustinegrass are most prone to this disease; large patch rarely causes significant damage to bermudagrass turf. Not all turf needs to be treated with fungicides to control large patch, but areas that have sustained severe damage in the past should be sprayed on a preventive basis.

One great advantage of the warm-season grasses is that they are fairly resistant to diseases; in most parts of the southeast, we only need to worry about one or two diseases on these grasses. Spring dead spot is a major problem on bermudagrass, and large patch can cause severe problems on all the others - zoysiagrass, centipedegrass, and St. Augustinegrass.

One problem with large patch is that it comes at a time when the warm-season grasses are shutting down for the winter or greening-up in the early spring. As a result, the potential for recovery once symptoms appear is slim to none. Once an outbreak occurs, you're probably going to be looking at those symptoms until April or May when the turf really starts growing again.

The other problem with large patch is that the appearance of symptoms is very unpredictable. Sometimes they appear in late summer, other times during the fall, and in many cases no symptoms are observed in the spring. So how are you supposed to prevent the symptoms if you don't know when they are going to appear?

The answer is easy - don't time your fungicide applications based on when symptoms have appeared in the past. Instead, you should time applications based on when the pathogen is active. As it turns out, we know that the large patch pathogen becomes active when soil temperatures consistently dip below 70 degrees at the 1 to 2 inch depth. In other words, NOW IS THE TIME TO START PREVENTIVE PROGRAMS FOR LARGE PATCH IN MANY AREAS!

There has been much confusion over the name of this disease, and as a result, very few fungicides are specifically for 'large patch'. Some labels still refer to the disease as 'brown patch', whereas others call it 'zoysia patch'. Since they are all caused by Rhizoctonia solani, any fungicide that has one of these diseases on the label can be used for large patch control.

In some cases, one well-timed fungicide application in the fall can provide season long control of large patch. However, in severely affected sites, where disease pressure is high, repeated applications are often necessary. Two applications in the fall, 4 to 6 weeks apart, and one application in the spring when the turf is nearing full green-up is the ideal program. If three applications are not possible financially, the fall applications are probably more important than the spring application.

Strong brown patch fungicides like Heritage (0.4 oz of 50WG or 2 fl oz of TL), Insignia (0.9 oz) and ProStar (2.2 oz) are very effective for large patch control. Some of the DMI fungicides, Bayleton (1 oz) in particular, have performed very well also. Recent trials have also shown that Headway (3 fl oz), a pre-mix of Heritage and Banner, is a very effective large patch fungicide.

For more information about large patch management with fungicides and cultural practices, please refer to our Large Patch Disease Profile on TurfFiles.