Is it Starting to Feel Like Groundhog Day?

So I bet many of you in the south are feeling like Bill Murray in the 1993 movie “Groundhog Day”. I know I am. Everyday we look at turfgrass samples with the same problem. Heat-related stress and decline and severe nematode populations! Many superintendents that I have spoken to are getting as frustrated as me. This heat is getting old. We are now sitting at 45 days above 100F here in Stillwater. In the Oklahoma City area they are knocking on the all-time record of 50 days! Everyday the same thing…

The OSU Turfgrass Diagnostic Laboratory has churned through a bunch of creeping bentgrass putting green samples in the last couple of weeks. The large bulk of samples have extremely short root systems. The heat has really taken its toll on creeping bentgrass in much of the south central U.S. Throw in some nematodes damaging what roots are left and we have a lot of turfgrass in serious decline. Very high populations of stunt (Tylenchorhynchus spp.) and ring (Criconemella ornata) nematodes have been observed in many of the samples submitted. We have seen populations of stunt nematodes as high as 4,000 individuals in 100 cc of soil. This is about 26 times the threshold we consider the “danger zone” on creeping bentgrass. Ring nematode populations have been coming in as high as 2,000 individuals per 100 cc soil, which is about four times the “danger zone” population level. So as you can see, things are getting tough here at the end of the summer in the south. Many are praying for cooler weather and rain. Although, those that have gotten rain have been struggling with wet greens and hot weather, which makes for a whole different set of hurdles.

Other issues in the diagnostic lab have been few and far between, but we did have one sample with Pythium root rot. This was an odd situation where the greens got dry and severe wilt began. To compensate the newly hired assistant superintendent turned the irrigation system on and severely over-irrigated multiple times. When you have lots of soil moisture and high temperatures in the rooting zone, Pythium root rot can help finish off the already declining plants. So while, not the initial cause of the problem, we did identify something other than nematodes. In our research plots, brown patch has also been active and dollar spot comes and goes pretty much as the humid weather comes and goes.

The long-term forecast is showing cooler temperatures, if we can just get through this weekend. As Dr. Kaminski has said in a previous post “there is light at the end of the tunnel.” So keep your head up and your fingers crossed for cooler temperatures, I think we will be there soon!

More on Nematodes in The Southern U.S.

The heat is still cooking us here in Oklahoma and the rest of the south-central U.S. We also have been receiving many samples in the OSU Turfgrass Diagnostic Laboratory. Most of the samples are suffering from severe heat-related stress. This past weekend has been one of the hottest we have seen yet here in Stillwater. According to the Oklahoma Mesonet station summary for Stillwater, we topped out at 105 F on Saturday and 107 F on Sunday. As I said in my previous post, if you are experiencing these temperatures and still mowing everyday at ultra-low heights, making cleanup passes on edges of greens, have your grooved rollers on, and are doing anything else that causes unneeded stress on turf plants, STOP! These practices will facilitate a quick decline of putting greens under these sustained high temperatures and there is nothing you can do to facilitate recovery until cooler temperatures (high temperatures less than 85 F) prevail.

In addition to samples that are under severe heat stress, we have been receiving many samples with high nematode populations. I talked about this in another post and Dr. Tomaso-Peterson also wrote a great synopsis on nematodes. We have been receiving some questions on how nematodes cause damage to plants so I’ll attempt to explain a bit using creeping bentgrass as the host of interest.

Nematodes cause damage on creeping bentgrass by feeding on the roots. Feeding by these tiny animals (roundworms) can injure and impair root functions such as water and nutrient uptake. Nematodes may feed externally or internally. Utilizing a specialized spear-like feeding structure (stylet), nematodes puncture plant cells in the roots, causing discolored areas (lesions) or swellings. Nematode activity also can predispose the grass to attack by other pathogens such as fungi and can cause the plants to be more prone to heat-related stress. Some of the most common plant pathogenic nematodes we find in putting greens in the southern U.S. include lance (Hoplolaimus spp.), ring (Cricinemella sp.), spiral (Helicotylenchus sp.), stunt (Tylenchorhynchus spp.), sting (Belonolaimus spp.), sheath (Hemicycliophora spp.), and root knot (Meloidogyne spp.). Female nematodes can lay many eggs (up to 500 eggs), which in turn hatch into juveniles. These juveniles will then mature through a series of four molts then becoming adults. Nematodes are motile in the soil for very short distances. Long distance spread occurs through surface water runoff and movement of infested soil from location to location. In non-tilled soil environments such as on a golf course, movement of infested sod is a primary method of dispersal. Generally speaking, sandy soils are more likely to have nematode problems than soils with a high clay content. Therefore, sand-based putting greens are a great environment for nematodes to flourish.

Above ground symptoms of nematode induced diseases will often resemble drought stress, general lack of vigor and little to no response to irrigation, fertilization or even fungicide applications. Symptom expression is directly related to the number of feeding nematodes. Nematode populations can increase very quickly in the summer months. The length of the nematode life cycle is partially regulated by temperature. As temperature increases, life cycles get shorter and the population of nematodes can increases at a faster rate. In addition, if we consider creeping bentgrass plants, as the heat increases, root and shoot growth can slow or stop. If roots have stopped growing (and maybe dying) due to high temperatures and there is a lot of nematode feeding, it is easy to see how creeping bentgrass plants can die very quickly without much warning. Further complicating matters, is the presence of multiple groups (genera) of plant pathogenic nematodes, which can have a synergistic effect on disease severity and symptom expression. The best way to confirm a nematode problem on a stand of creeping bentgrass is to have a soil sample evaluated. These assays are usually expressed in numbers of individuals of different nematode genera per volume of soil. Various treatment threshold numbers have been established for some nematode genera on certain turfgrass types.

Management options:
Few chemical fumigants/nematicides exist as options for controlling plant pathogenic nematodes. Therefore, superintendents should practice methods to promote a vigorous root system on creeping bentgrass plants in the spring before stressful growing conditions prevail in the summer months. I have written before about managing nematode-induced stress. However I will reiterate here. Cultural management should include raising mowing heights (.160 in. or more would be advised), adjustment of the frequency of mowing and rolling to reduce the amount of stress applied to the turf stand, and continued frequent, light applications of fertilizer and water are recommended. Any practice that reduces stress and damage to turf plants will assist the plants in surviving the additional damage that nematode feeding causes. Regular soil assays should be done if nematode activity is suspected.

Dr. Nathan Walker and myself have various experimental chemical treatments that we are evaluating for efficacy toward nematodes. In future posts I hope to comment and show some data. Hopefully we will have something positive to present. Until next time…

Greetings from the hot, humid, and dry Deep South!

Greetings from the Deep South! I am Maria Tomaso-Peterson, Ph.D and come to you from Mississippi State University where I conduct research and teaching in turfgrass pathology. I am very pleased to be invited by my fellow turfgrass pathologists and bloggers to participate in sharing insights from the Gulf Coast States.

The first half of 2011 has been coined the year of extremes…….. no, I am not referring to politics, but to weather conditions across the United States! South of the Interstate 10 corridor, rainfall deficits are making their way into the record books. Our fellow superintendents in Texas are experiencing the driest seven months on record. When I visited New Orleans, LA in May, I was amazed at the drought stress exhibited by the palm trees along Canal St. South Mississippi and Alabama, as well as the panhandle of Florida (the whole state, actually) are well below average for annual rainfall.

With that, fungal disease pressure has not been the issue thus far. The primary challenge is delivering adequate water to keep the turf alive. Of course, the greens are the primary receivers of irrigation, followed by tee boxes, and fairways (sparingly). The roughs have gone dormant, but not to worry, the bermudagrass will be back! Despite the dry conditions, there are still some pest issues that have to be managed. I thought I would share some of those issues with you in my inaugural blog post.

My fellow turf pathologist out of Oklahoma State University, Dr. Damon Smith, had an excellent review on nematodes in creeping bentgrass back in June. As we know, sand-based putting greens are an ideal environment for plant parasitic nematodes; couple that with root zone temperatures above 65 F for the better part of a growing season in the South, one can see how nematode populations can get out of control in one growing season. Sting and root knot nematodes are the most common species identified from dwarf and ultradwarf bermudagrass putting greens. At the Mississippi State University Nematology Laboratory, analysis results have shown bermudagrass green samples with sting in excess of 500 per 100 cc soil and other samples with root knot greater than 1,200 per 100 cc soil. The affected areas of a bermudagrass green may appear light green to yellow, thin turf density, reduced clippings, and the turf does not respond to nitrogen or irrigation. The damage may be widespread but more often observed in clusters. Symptoms of sting damage on bermudagrass roots (left) include root-pruning and necrotic lesions. Root knot galls are easily detected under a stereomicroscope.

In the photos below, root knot galls can be seen in bermudagrass roots (left) as well as pearly-white, mature female root knot nematodes embedded in a bermudagrass root (right).

For those who stock-piled Nemacur, spot treatment is recommended for control. Curfew® is a soil fumigant which requires a custom applicator and is labeled for use in Mississippi, Alabama, and Florida. Curfew has been granted a 24(c) label from EPA for use on golf courses in Texas and Louisiana. Non-fumigant products, some biologically-based, are also commercially available for nematode control.

Another pest that has been active on drought-stressed turf is the bermudagrass mite (BGM), Eriophyes cynodoniensis, which can be found wherever bermudagrass is grown throughout the United States. Mite injury is most severe to bermudagrass during hot and dry conditions such as those experienced this growing season.

The BGM feeds underneath the leaf sheath. Once feeding commences the leaf tips turn yellow and the leaves become twisted. The internodes shorten resulting in a rosette or witch’s broom appearance. Under severe outbreaks, large areas of turf turn yellow, thin out and may die as a result.

Insect damage was observed on bermudagrass fairways and roughs earlier this month in Texas. When infestations are high enough to cause obvious symptoms of BGM damage, it is necessary to irrigate the affected turf to minimize damage to the plants. Insecticides are available for BGM control; however repeat applications are necessary to reduce the populations.

Several locales along the Gulf Coast have received rain over the past week. These localized rain events are a welcome sign for those folks in the drought-stricken regions. The rains drive up the humidity in the turf canopy which in turn is favorable for disease development. I will be scouting the Deep South for disease outbreaks so I can report back to the Turfgrass Disease Blog in the near future. In the meantime, just remember…..never underestimate the power of a fungus!

Rounds4Research Beginning to Pay Big Dividends

Visit Rounds4Research.com to find out more!

Due to the slumping economy, state governments across the country are struggling to meet huge budget deficits. This almost always means significant budget cuts at land grant universities that do turfgrass research. Some have been cut worse than others, but we're all feeling it in one way or another.

Most people don't realize that we receive little to no resources from our universities to run our programs. You want to hire a technician? Fine, come up with cash and then maybe HR can make it happen. Need to drive across the state to give a talk? You can go wherever you want if you can pay the gas bill. You want a cell phone? Sure, if you have the money you can do that too.

That's why the financial support that we get from the turf industry is so important. Without it, we can't do a thing. This is also why the recent decline in research funding from national organizations like the USGA and GCSAA is so troubling.

Many of the southeast's best golf courses participate in R4R

For as long as I can remember, people in the turf industry have been asking "How do we get the golfing public to support turfgrass research?" Several years ago, Tim Krieger of the Carolinas Golf Course Superintendents Association initiated Rounds4Research to do just that. Golf courses and resorts can donate rounds of golf or vacation packages to be auctioned off to the general public, with the proceeds going to support turfgrass research in the participating states. The Carolinas, Georgia, and Virginia are participating in 2011.

Last fall, the Carolinas GCSA funded 4 research projects at Clemson and NC State for a total of $94,225. The funded projects aim to address major issues like water conservation, nutrient fate, doveweed management, and perhaps most importantly, nematode control. Bruce Martin and I are collaborating on the nematode project, which I will write more about in the coming weeks.

If you have problems with nematodes, or just want to support turfgrass research in the Carolinas, Georgia, or Virginia, then it's not too late to participate in the 2011 Rounds4Research auction. Donations of rounds and golf packages are being accepted until April 4, and the online auction will run from April 10 to 17. All of the details can be found at rounds4research.com. Please help by encouraging your facility to donate, and also by spreading the word to golfers at your club about this rare opportunity to play golf at some of the nations top golf courses!

Anthracnose, Summer Patch, F-bombs, Nematodes and Cee Lo

Anthracnose & Summer Patch in California

'Hey - Did-ya Miss Me?' Anthacnose was plentiful in the UCR diagnostic lab this week

I was back in California this week and greeted with triple digit temperatures - normally I'd say the dry heat of California is better than the steamy heat of Washington DC, but 112 degrees in Riverside was still pretty bad!

I always say that anytime we get wide temperature swings, anthracnose is likely to rear its ugly head, and this last week was no exception - Naveen was getting quite a few of these samples in the lab.

As John had mentioned earlier this week, summer patch has been pretty active on annual bluegrass greens and we saw it on a few samples in California as well. Back in the 'good old days' of the 90's, it seemed like anthracnose and summer patch control went hand in hand, but recent developments have resulted in some 'complications'.

As we all know, anthracnose has become the primary concern of most guys out there with annual bluegrass greens, but summer patch can often be a hidden problem. Here are two observations regarding summer patch development this year.

#1 Targeting Anthracnose but Forgetting About Summer Patch
Sixty-five to sixty-eight degrees soil temperature in the spring is the magic range for initiating anthracnose & summer patch control programs with 2 to 3 applications of DMI-fungicides like Banner MAXX, Trinity, Triton, Tourney or Torque, but after that, control diverges quickly for these diseases. Fungicides like the Heritage (azoxystrobin) and Insignia (pyraclostrobin) are my top choices for summer patch control (thiophanate-methyl, e.g. 3336, is also a consideration), and should be applied monthly in the summer to keep summer patch in check. But....as we all know, anthracnose resistance to the QoIs and benzimidazoles in many locations makes these ineffective for anthracnose control. For mid-summer applications, products like chlorothalonil (Daconil), fludioxonil (Medallion), polyoxin-D (Endorse/Affirm) and Signature (Fosetyl-Al + StressGard pigment) are my go to materials. DMIs can also be effective, but applied in the summer heat may cause some unwanted PGR effects.

Superintendents worried primarily about anthracnose may be applying anthracnose-fungicides but forgetting to use Heritage & Insignia on a monthly program. As a result, summer patch can break through what seems like a good program that is unfortunately tailored specifically for anthracnose.

#2 Compass vs Insignia in Rapid Blight Control Programs & Effect on Summer Patch
Rapid blight is another disease that California superintendents battle in the spring and summer, and Compass (trifloxystrobin) and Insignia are the 'go to' systemic fungicides for rapid blight control (mancozeb is our only contact option), but differ in their physical properties. Compass is very strong as a foliar fungicide, but less systemic than Insignia and will not give you effective summer patch control. If you've been using Compass regularly in the summer, remember that you could be under-gunned for summer patch control, and have to apply additional materials.

Bottom Line: Anthracnose, summer patch and rapid blight management require specific fungicides - choose wisely and know what fungicides won't give you any overlap in disease control.

Anthracnose Rescue Fungicide Programs
If you have anthracnose breaking out on greens, it is most likely that you (i) have had a serious stress event, (ii) are too lean on fertility or (iii) have had a lapse in fungicide protection in your program.

Notice that 2/3 of the 'issues' are not fungicide-related. Correcting cultural practices and fertility is the top priority, but here are some thoughts on a 'rescue' program for active anthracnose outbreaks.

1. DO NOT BOMB IT WITH QOIs/STROBIES OR T-METHYL FUNGICIDES EVEN IF THEY STILL WORK FOR YOU. That is a recipe for resistance, big time! Anthracnose is already a high-risk pathogen when it comes to QoI and benzimidazole fungicides, and using them as 'eradiciants' in this way increases the chance of selecting out resistant populations.
2. CHLOROTHALONIL IS YOUR FRIEND. This is partially why I encourage guys to save up some of your 10 or so chlorothalonil applications for the summer. Chlorothalonil will not 'cure' existing infections, but can kill spores developing in acervuli and prevent new infections (if you let your foliar anthracnose go all the way in to the crowns, you're hosed, don't wait til that happens as you won't be able to get on top of it with fungicides in the summer). Being a contact fungicide, you will need to apply frequently to ensure that you have lasting coverage on plants. Applying the normal label rate, at a shorter application interval, is likely more effective than the max. rate once or at longer intervals.
3. MEDALLION, ENDORSE & AFFIRM --- These are 'limited systemic' fungicides and can give you added control of anthracnose, but are at moderate risk for fungicide resistance. I would not encourage them to be used as 'eradicants' but you can apply them to help with protecting plants once you have the active outbreaks arrested with aggressive chlorothalonil use. Right now, there is no resistance to these, & we want to keep it this way for the time being.
4. SIGNATURE, ALIETTE, & PHOSPHITES --- These have for the most part, 'indirect effects' on anthracnose, and will not work as 'eradicants'. The data I've seen shows that the active molecule in these fungicides is not super-toxic to anthracnose, and provide protection via induced plant defenses or other mechanisms; and you guys know how I feel about StressGard pigment being a good thing for annual bluegrass in the summer. Tank mixing them with your chlorothalonil will give you added protection but they will be acting on healthy plants vs. new infections and not directly killing the active anthracnose.

F-Bombs, Nematodes and Cee-Lo
Ok - I've gotten some (for the most part) good natured ribbing from some guys this week about my comments on Turf Net regarding what we know about nematodes.

http://www.turfnet.com/view_news.php?obj_id=606

Call me crass, but the F-word is strongly correlated with the discussion of turf diseases; it's one of those words that in its various forms has use as a noun, verb or adjective, especially when discussing anthracnose, summer patch or rapid blight, and annual bluegrass in general.

On the other hand, in all seriousness regarding the comments, we really don't know enough about nematodes on turf, and really really don't have enough chemical controls for the problems - making me drop the F-bomb to drive home the point.

Compared to the 30 or so university turf pathologists in the US and dozen or so different fungicide active ingredients, we have like 4 turf nematologists (Crowe, McClure, Wick & Mitkowski come to mind) and 1 nematicide (Curfew), plus any Nemacur stockpiled in the shed, that can control nematodes down in the soil .

You know I love me some fungus, but considering the issues caused by nematodes like root knot, stem & gall (Anguina), spiral, sting and others, and more importantly - the high amount of "mis-information" about nematodes and their control out there - it's a good time to put some attention and funds towards this. That's my 2% of a dollar.

Finally, if you can't get enough of the F-Bomb, check out Atlanta-based Cee Lo's new music single and song here:
http://www.youtube.com/ceelogreen#p/u/1/CAV0XrbEwNc

(WARNING: DEFINITELY NOT SAFE FOR WORK OR CHILDREN)

If you're not offended by the F-bomb and like Old School Motown-Style R&B, it's certainly worth a listen. I suspect they will have taken this one down from the internet by the time you read this blog today, but I'm sure you'll hear about this one soon.

OK - Back in DC as of the Morning and Signing off from the Right Coast.....

Summer Stress Programs for Desert Bentgrass in CA

Developing a Summer Stress Fungicide Program for Coachella Bentgrass (and the Case of the Mysterious #13)

This is a follow up on something I been meaning to address but spurred on by an email I received this week:

Dr. Wong,

I am a Golf Course Superintendent in the Palm Springs area and manage Penncross putting greens. As we both know, heat and cool-season grasses don’t work well together.

Currently we are experiencing exceptional summer bentgrass decline due to high heat and humidity. Are there any fungicide trials or protocols that other Superintendents may be using to minimize effects of SBD? We have fans on each greens, and water as needed with syringing during the day. Our heights are .150 and mowed every other day. Other than that we try to keep them alive.

Hot in Coachella

Yes, bentgrass and triple digit temperatures through the summer get along as well as Meg Whitman and Jerry Brown in California. Based on work done at NC State by Turfgrass Specialist Art Bruneau, cool season turfgrass growth pretty much declines rapidly when 4-inch deep soil temperatures reach 70°F with root and shoot growth completely shutting down at 77ºF and 90ºF, respectively.

http://www.turffiles.ncsu.edu/articles/tf00766.aspx

With soil temps in the California desert hitting 70 to 90ºF from April to September, it means a long late spring through the fall of tough conditions for superintendents in the desert (including other areas in the SW like Arizona, New Mexico and Nevada) who have to hold onto their bentgrass year round.

Although fighting Mother Nature through this period can be partially successful using fans and syringing; in any case, simply put the high temperatures will result in poor growth and recovery from the bentgrass magnifying any damage caused to the turf by mechanical, environmental or pest stress.

From a pathologist’s point of view, the diseases that would likely cause the most damage to bentgrass in this climate would be takeall patch, Pythium blight , Curvularia blight and algae.

Month	Avg. Hi	Avg. Low	Avg. Prec.
Jan	70°F	44°F	1.27 in.
Feb	75°F	47°F	1.15 in.
Mar	80°F	51°F	0.63 in.
Apr	88°F	56°F	0.08 in.
May	95°F	63°F	0.06 in.
Jun	104°F	70°F	0.05 in.
Jul	108°F	76°F	0.19 in.
Aug	107°F	76°F	0.40 in.
Sep	101°F	71°F	0.39 in.
Oct	91°F	61°F	0.11 in.
Nov	78°F	50°F	0.29 in.
Dec	70°F	43°F	0.61 in.

Take all typically infects and damages plants in cool wet weather through the fall and winter. Symptoms can often show up under periods of heat stress because plants with damaged roots simply can’t efficiently use water to keep themselves alive. In the desert, the high temps really hamper the ability of the turfgrass to recover and regrow, magnifying take all damage on bentgrass greens. I won’t cover it much here, but soil pH and manganese management coupled with preventive fall fungicide applications work best for preventing problems with take all.

Pythium blight is a real threat to cool season turfgrass when night time temperatures stay above 68ºF and there’s adequate moisture to trigger fungal growth and spread. There’s an excellent review of Pythium here at the Rutgers website:

http://www.turf.rutgers.edu/research/diseasecontrolseminar/pythium.pdf

Believe it or not, but Curvularia blight is pretty common to find on bentgrass coming from the desert. Curvularia can often be considered a wimpy disease that only attacks weakened or nearly dead bentgrass, but like anthracnoseon Poa, it can be the nail that closes the coffin on your summer stressed bentgrass if not controlled.

Alage can also turn up commonly as it’s quick to colonize wet surfaces and thinned out bentgrass in the summer.

The Mysterious Program #13

As detailed in the Pythium presentation above, Bruce Martin at Clemson is credited with developing a fungicide spray program (#13) that has worked very well for managing diseases on creeping bentgrass in the southeastern U.S.: http://www.usga.org/course_care/regional_updates/regional_reports/southeast/Program--13-Still-The-Best-At-Dr--Martin-Fungicide-Trials---December-2008/

The question posed by several Coachella Valley superintendents has been “how well does #13 work in California?”

Well, Bruce’s #13 provides broad spectrum protection vs. a number of summer diseases while using some of Bayer’s “Stress Gard” pigmented materials, and Insignia which BASF is reporting to promote plant health. But….the southeast gets a lot more humidity and #13 is also designed to pick up brown patch and dollar spot; it’s just too dry in Coachella to have these figure as major players in a summer disease profile.

Looking at #13, applications start in late May in the southeast and go at 14-day intervals; here’s the break down with likely targets of activity.

May 22: Tartan 2.0 fl oz --> brown patch/dollar spot control

June 5: Insignia 0.9 oz --> broad spectrum disease control

June 19: Spectro 90 5.76 oz --> broad spectrum disease control (no Pythium actvity)

July 3: Signature 4.0 oz + Daconil Ultrex 3.2 oz --> Pythium control, algae control, stress reduction

July 17: Insignia 0.9 oz --> broad spectrum disease control

July 31: Signature 4.0 oz + Daconil Ultrex 3.2 oz --> Pythium control, algae control, stress reduction

August 14: Chipco 26GT 4.0 fl oz --> brown patch/dollar spot/Curvularia control

August 28: Tartan 2.0 fl oz --> brown patch/dollar spot control

OK – if you discount the presence of dollar spot and brown patch in Coachella, you can see some of these applications would not be necessarily applicable. Also with regard to Tartan which is a mix of Compass and Bayleton, applying a DMI (Bayleton) isn’t necessary, especially if dollar spot pressure is absent. Spectro probably isn’t needed as much, again due to the lack of dollar spot and brown patch pressure.

Pythium pressure is likely to come from June through September with high night time temperatures. Insignia and Signature + Daconil applications would probably give some significant benefits during this time for both Pythium and “plant health benefits”. Although other Pythium-specific fungicides like Subdue, Banol and Stellar could be used, I would save these for overseeding type situations or when you know that hot wet weather is coming. Otherwise, it may be fine to rely on preventive applications of Signature or other phosphonate/phosphite type products during the summer. Although many of the phosphonate or phosphite type products do a very good job of controlling pythium and improving plant health, the “Stress Gard” pigment in Signature is something I think works pretty well as an added layer of stress relief for your turf.

I’d see Curvularia as a constant threat through the season, but it may not be worth using a 26GT application specifically for this disease, when you can get control with other materials.

A contact fungicide like mancozeb (Fore) may work just fine in Coachella for keeping pathogens like Curvularia at bay, plus beating back algae.

So…in putting all of this together, I’d say that #13 is a great program, but not necessarily well fit for southwestern desert bentgrass greens.

Looking at the situation, maybe something like this would work:

May 15: Fore 8 oz

Jun 1: Insignia 0.9 oz

Jun 15: Fore 8 oz

Jul 1: Signature 4.0 oz + Daconil Ultrex 3.2 oz

Jul 15: Insignia 0.9 oz

Aug 1: Signature 4.0 oz + Daconil Ultrex 3.2 oz

Aug 15: Fore 8 oz

Sep 1: Signature 4.0 oz + Daconil Ultrex 3.2 oz

Sep 15: Fore 8 oz

Keeping the Signature and Daconil in the mix as a stress & algae application; Insignia as a 28-day preventive early in the summer and regular applications of Fore to clean up algae and clean up “junk” diseases like Curvularia may work just fine.

I’d like to see some research in Coachella to support the suggestions, but this type of program may be a good starting point. If you think "there goes Dr. Wong, smoking the crack again." - that's fine too; I think it's good to have some discussion about what is working for guys in the desert who are growing bentgrass.

Bottom line: programs like #13, are very good, but may not cover the diseases & stresses unique to the southwest – think about what you’re trying to fight and design a program around that.

A Few Thoughts about Nematodes

One thing that needs some attention as far as bentgrass greens in Coachella is the presence of some new root knot nemtaodes found affecting cool season turf. Very high populations were associated with severe damage at a few locations in Coachella in 2009. As discussed above, the summer stress for growing creeping bentgrass in Coachella is already pretty high – nematode populations really need to be considered in this equation.

This is a green from 2009 in Coachella that took some severe nematode damage; don't let this be you!

If you’re growing bentgrass in the Valley; it’d be worth having a test done to see if you need to worry abouyt these critters as well.

OK – until next week – signing off from the Right Coast…..

European Turfgrass Society Conference

Two weeks ago, I had the opportunity to attend the European Turfgrass Society (ETS) Conference in Angers, France. This was a great opportunity to find out what other turfgrass researchers around Europe as well as other parts of the world are currently researching. With so many turfgrass programs and scientists in the United States, it is often hard to see a diverse group of talks at any one show. For instance, scientific conferences in the United States are usually sectioned into various disciplines such as soils, pathology, physiology, entomology, etc. For this reason, I end up migrating to the pathology and more golf-related talks and often miss a lot of other things going on in turfgrass research.
At the ETS conference, all talks are given in one session spread out over several days and mixed with various opportunities to meet and discuss the latest and greatest turfgrass trends with people from across the globe. Below are some highlights of things that I found particularly interesting at this year's conference.

1. Plant Parasitic Nematodes: Kate Entwistle of The Turf Disease Centre in the UK talked about the increase in nematode activity on cool-season turfgrasses in Europe. The potential for nematodes to cause damage to cool-season turf has been a bit controversial (in my opinion) over the last few years. Many "pathologists" often suggest that any turf that cannot stand the presence of some nematodes probably has other issues more pressing than the nematodes themselves. On the other hand, many "nematologists" often state that these pathogens are in fact the primary cause of many problems. Either way, it does appear that more and more cases of this problem are showing up. Dr. Entwistle stated that some of the main differences among species found in the USA vs. Europe is that the predominant species in the Europe are Meloidogyne and Hilcotylenchus.
   
2. Induced Systemic Resistance of Civitas: Dr. Tom Hsiang of the University of Guelph gave another entertaining (Great Introduction about Guelph...I may steal that one) and informative talk about his work to prove that the relatively new horticultural oil Civitas works by inducing natural plant resistance mechanisms. Utilizing Induced Systemic Resistance-related genes, his lab found that the enhanced expression of two jasmonate related genes following treatment with Civitas and inoculation of the M. nivale pathogen. In controlled experiments, Dr. Hsiang also found that Civitas reduced three diseases (dollar spot, brown patch, and Microdochium patch) by 20 to 40% when compared to an inoculated control. Based on field trials presented on this site and by some colleagues, Civitas has been shown to reduce certain diseases, but more field work is needed to work out programs and acceptable tank-mix combination's to provide complete disease suppression.
   

3. Preparation for the 2010 World Cup: Although not a scientific presentation about ongoing research, the talk by Dr. A.S. Schoeman on the preparation of the pitches for the World Cup was one of my favorite talks. Dr. Schoeman had a great fluidity to his presentation and gave some interesting facts about the upcoming events. This is the first time that Africa has hosted the World Cup and matches will be played at 10 different venues throughout South Africa. In addition to the ten stadiums, 15 training sites will be utilized and 3 sites will be used exclusively by the referees (what the heck do they need these for?). An interesting component to the preparation is that this will be the first time that matches will be played in HDTV, making the preparation that much more important. Other interesting points include:

• Most pitches will have Kikuyugrass as the base, but will be overseeded with perennial ryegrass and Kentucky bluegrass
• Logos (currently used for advertising during Rugby matches) will need to be removed prior to the event since these sponsors are not the same for the World Cup.  Current sponsors are asking that their logos be applied with "extra paint" which will make their complete removal more difficult!
• A few stadiums have "cannon" style irrigation and therefore it will be difficult to pre-dampen the fields (as some teams request) prior to the game without soaking the spectators as well.

For those academics who didn't get a chance to make it to this year's conference, it is a good time to start some relevant research for the European market. The next conference will be held somewhere in England (probably London) in 2012 to coincide with the summer Olympic games. I look forward to attending ETS in 2 years and just hope that mother nature (e.g., the Iceland volcano) cooperates a little better than this year. (Full story on this on Monday).

Stress & 'todes

It’s always hard to follow Frank’s posts. I mean, what can I write after he applies “If it’s yellow, let it mellow” to turf disease?

The big concerns lately have been brown patch, foliar Pythium, stress, and nematodes.

While brown patch seems to have decreased somewhat from our surprise late June epidemic, I suspect that it will come surging back in with our forecasts of more heat, humidity, and rain.

Dollar spot has totally disappeared from our research plots. Too hot!

As for foliar Pythium, the rains keep coming, nighttime lows remain high, and the sites with the disease are on high alert. Most have put down one or more applications of a Pythium fungicide and are watching for new activity.

Stress? That is on the plate every week. In some recent samples, waterlogged soils have clearly caused root decline with some secondary Pythium nibbling on the aftermath. We still can’t seem to dry out in some areas.

The photo illustrates a stress problem where greens received a little too much N, got puffy, then scalped. You can see the scalped spots right at the edge where the mower hit the green.

Nematodes in turf are a tricky subject. There was a lot of discussion earlier this week amongst turf pathologists about damage thresholds in nematodes. Damage thresholds are hard to pin down, and the potential damage of a certain population of nematodes varies with the overall amount of stress at the site. Sometimes there is a correlation between turf damage and nematodes; often there is not. Usually there are multiple factors in play.

One nematode that is pretty well documented to cause damage even at low numbers is sting nematode. We picked up sting in a sample a few days ago. I heard Dr. Mike Fidanza (Penn State) joke one time, “If you want to spread news, what are the 3 best ways to do it? 1) Telephone. 2) Telegraph. 3) Tell-a-superintendent.” That is, news travels fast in this industry. After the sting finding, we had a sudden flush of requests for nematode testing because the word had gotten out. Numbers of all plant pathogenic nematodes were pretty low, and no sting nemas were detected anywhere else.