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....

Instrata (Chlorothalonil + Propiconazole + Fludioxonil)

Instrata is another fungicide that combines different active ingredients into a single product. Instrata has chlorothalonil (Daconil and many others), propiconazole (Banner MAXX and others) and fludioxonil (Medallion). Instrata quickly became the gold standard for snow mold control in northern climates like the Upper Midwest. Interestedly the formulation of this product combined suspended particles with a microemulsion that Syngenta calls a suspomicroemulsion. I really don't know what that means for golf course superintendents, but you have to admit it sounds cool! All kidding aside, we typically suggest that active ingredients should be mixed in order to achieve acceptable snow mold control. With Instrata you have three active ingredients that when combined do provided excellent snow mold control. Chlorothalonil is a contact fungicide that has activity on all three snow mold pathogens (Microdochium nivale, Typhula incarnata and Typhula ishikariensis), but is strongest on M. nivale and T. incarnata. Propiconazole is a DMI fungicide, which are known to have excellent activity on T. ishikariensis and fludioxonil seems to have activity on all three snow mold pathogens too.

For those who manage golf courses in areas that receive intense snow cover will likely experience all three snow mold pathogens at one time or another. I think the reason Instrata is a successful fungicide for snow mold control is golf course superintendents don't have to worry about predicting the weather because all the product works on all three snow mold pathogens. With respect to efficacy of Instrata, I have posted a few figures highlighting how well this product works. We do see breakthrough at our site in the UP, which has intense snow mold pressure. Yet, for the last two years we observed that 70 % of the products break down under that pressure. Even under that pressure, a single application of Instrata keeps disease severity levels between 15 and 40 %. Anyone that experiences such snow mold pressure should make two applications for snow mold and we observed that two applications of Instrata at 5.5 oz worked better than a single late application of Instrata at 11 oz at our UP site. For most golf course superintendents however, the 9.3 oz rate will work beautifully! A word of caution about the product, do not skimp on the rate in areas of high snow mold pressure. We have observed that reducing the rate to 5.5 oz in some environments may result in significant failure.

In summary, Instrata is an excellent combination fungicide for controlling snow mold diseases. It also has activity on other diseases too, which is obvious based on the active ingredients in the product. Instrata is an excellent choice for putting greens and tees and if the budget allows high value approaches and maybe even fairways. If you are interested in this product and have not used it before check out the label and Syngenta's website for more information.

Another Good Winter for Snow Mold

As Megan mentioned we got hammered with snow last week. The total snowfall amounts vary but we received over 15 inches of snow! Yes it took me most of the day on Wednesday to clear my driveway, but a wonderful neighbor used his bobcat to clear "plow trash" at the end of my driveway. The picture was taken last Wednesday morning and I was clearing a path for my dog to use the restroom. Following the snowfall, temperatures plummeted! The high last Thursday was 7 and the low was -4, so I think the snow is going to stick around a while.

With the amount of snowfall we received last week that fell on unfrozen ground, it appears that this winter is going to be conducive for gray snow mold development. Gray snow mold is induced by two Typhula species- T. incarnata and T. ishikariensis. Other names for the disease are Typhula blight and speckled snow mold. All cool-season turfgrasses are affected by gray snow mold, but the degree of severity differs with turfgrass species and the length of snow cover. Persistent snow cover provides an ideal environment for the gray snow mold pathogens to thrive and infect turfgrasses. If snow cover persists for more than 60 days than gray snow mold is likely to be problematic. When snow cover persists for more than 90 days, gray snow mold is often very severe. It is important to have an idea of how long snow persists in your location to develop a successful gray snow mold management program. Fungicides that are efficacious in areas with low to moderate snowfall may not be effective in areas with high snowfall amounts. I know I have posted our snow mold trials before, but it never hurts to repeat things. The reports clearly state how much snowfall was recorded at testing location. So pick the most appropriate site based on your conditions and hopefully you can find a chemical or mixture of chemicals that work for your budget.

What happens if we experience a winter thaw do I need to reapply fungicides? This is a question we routinely get, however I have yet to experience a winter thaw. I know I have only been here for one winter, still the last couple of winters have been fairly harsh. It is frivolous to apply fungicides when the ground is frozen, so that is the first thing to check. If the ground is not frozen then the answer is maybe. We are working with commercially available ELISA (enzyme-linked immunosorbant assay) kits to determine how long chlorothalonil and iprodione persist under snow cover and in the absence of snow cover. This technology is used to determine fungicide concentration in fleshy fruits like apples. We have just received some new data that demonstrates that our extraction method works very well and we are eagerly working on collecting degradation data this winter. Along with determining how these fungicide degrade, we are performing inoculations in the growth chamber to figure out when we lose protection to Microdochium nivale. There is more to come with this research so please stay tuned!

One interesting side note we learned from this project is the actual concentrations of the pesticides in the bottle/tank and what is detected on the plant. For example, Daconil Weatherstik is 54% chlorothalonil, when mixed in 2 gallons of water per 1000 sq ft the concentration of the solution drops to about 16 %. Then once the chemical is applied and allowed to dry for one hour we can detect about 600 parts per million on and within the leaf. I don't know if anyone else thinks those are interesting numbers, but I sure did. This spring we are going to repeat this experiment and we plan to include a sample to test fungicide concentration directly from the nozzle.

Best wishes for a happy holiday season and a happy new year to all of our readers! I am heading to North Carolina this Saturday for the holidays, so this will likely be my last post for the year. Thanks to all of the readers and thanks to John for putting the blog together!

Jim