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Our spring weather roller-coaster has continued through the first 3 weeks of May.
Since April 30, we have had 7 days over 85 F in the Chicago area with temps exceeding 90 F at Midway Station and reaching 89 F at O’Hare Field on both May 15 and 16 (record high temps).
That is 10-15 degrees warmer than normal.
Central Illinois has also been very warm, with 11 days over 85 F in the last three weeks reported at Bloomington-Normal.
Those hot, windy days of mid May followed a couple of cold mornings with significant frost on May 12 and 13 (Mother’s Day weekend).
April was 4 degrees warmer than normal, and May could also be several degrees warmer than normal if the heat keeps up...
Makes you wonder what July and August are going to be like, doesn’t it??? (So far in 2001, we are much warmer than we were at the same point in 1999...)
Fortunately, a "dramatic" cold front is working its way through the Midwest this week, and temperatures are expected to remain in the low to mid 50s with off and on rain showers until Saturday the 26th.
There was a nice little snow storm with high winds yesterday in Denver, where the temperature dropped almost 40 degrees in less than an hour - I bet that was refreshing!
(The talking heads on the weather channel were calling this front "dramatic" - I think "overdue" may have been a better term!).
Diseases
With the uneven weather conditions we are facing, there are a number of disease organisms that could be active, from some fairly warm weather bugs like "Sclerotinia" dollar spot, to the pseudo-snowmold Microdochium nivale.
In fact, during and just after the warm weather of last week, I received a number of reports of active ‘early stage’ dollar spot, especially across central Illinois (from Danville to ‘Chambana’ to Bloomington and Peoria).
Symptoms were mild for the most part, with spots about the size of a dime or maybe a nickel.
If you have Poa trivialis patches in your bent / poa fairways, you can scout for early dollar spot development by watching the ‘triv’ patches, since dollar spot seems to start there first, then spread to the bentgrasses.
If it stays cloudy, wet, and cool this week, I suspect there could be a pretty significant outbreak of Fusarium/Microdochium patch.
Don’t forget, M. nivale is the same fungus that causes pink snow mold during the winter; so if you had some pink snow mold around in February, the pathogen could make a return now.
(I saw evidence of this on Friday at a course along the North shore of Lake Michigan).
Symptoms can be variable, but usually involve a small circle about the size of a silver dollar that has a yellowish to copper color, and may have a grayish outer edge (smoke ring).
Also, at this time of the year, M. nivale seems to be more inclined to attack Poa annua and not the bentgrass.
I have also found some basal stem rot anthracnose on Poa annua, as well as the common faint yellow rings caused by Rhizoctonia zeae and related fungi.
BSR anthracnose could be severe this spring and early summer, since the Poa went through a tough winter and may be weakened by earlier crown hydration-freezing or snow mold damage.
Anthracnose can be distinguished by scattered areas of (primarily) Poa annua turf that develop bright yellow flecks or spots the size of a dime, and by the distinctive black fungal decay at the base of infected plants (hopefully have some nice pictures of this on the website soon!).
Another question/comment that I frequently hear this time of year has to do with off color patches of bentgrass in greens and fairways, which is often blamed on "leaf spot."
I do not think leaf spots or other fungal diseases cause these patches, but instead it is a response of certain bent clones to adverse environmental conditions.
The adverse conditions usually involve a late hard frost (such as we had morning of May 13), especially if combined with an abrasive topdressing just before the cold spell.
The adverse conditions could also involve a sudden hot and dry weather pattern (e.g. in central IL last week), or a borderline "safe" herbicide application (don’t forget bents are sensitive to phenoxy herbicides - see below).
In any case, I have never found a true Helminthosporium type leaf spot on these ugly bent patches in spring, although the injury may lead to minor leaf fungi infecting weakened plants (and might explain why some relief is often observed after a Daconil type application).
Insects
Mound-building ants continue to be a major problem on fine turf areas this spring.
There are a couple of new insecticides and bait products that are being tested this year for ant control, I will try to keep tabs on how the products perform.
Don’t forget, there is a fairly effective bait available now called Maxforce.
The first black cutworm invaders were observed across central Illinois (and Indiana) as early as the week of May 7.
All of that warm air blowing up from the south the last few weeks probably carried quite a few adult moths up this way, so they will be laying their eggs on a golf course near you.
If you see birds pecking at the turf and you find small holes with grass eaten away from the edges, cutworms are probably the culprit.
Another black bug, the dreaded black turfgrass ataenius (BTA) has been spotted on golf courses in central Illinois.
Overwintering BTA adults are coming out of hiding and looking for a place to mate and lay eggs.
These small beetles are often found wandering around on putting greens in the AM through the middle of the day (check the mower baskets!).
Insecticide applications to control BTA grubs can be made in the next few weeks, which will prevent visible turf damage in late July to early August.
We may get two cycles of BTA in 2001, since they seem to be active fairly early in the season.
Check out the information on black turfgrass ataenius in a recent edition of the U of I’s Home, Yard, and Garden newsletter - http://www.ag.uiuc.edu/cespubs/hyg/html/ (No. 4, May 16, 2001).
There is also a note there about the honey locust plant bug.
Has anyone seen any damage from this insect yet this year?
Weeds
As I mentioned in the last update, moss is becoming a chronic problem on many putting greens in Illinois.
Some early success has been reported with a new product called TERRACYTE, which is sold by Biosafe Systems of Glastonbury, Connecticut, and is distributed locally by Simplot Partners (and perhaps others?).
Terracyte is similar to another Biosafe product - Zerotol - in that it contains a peroxide component that releases an ‘active’ oxygen ion in solution, which oxidizes any nearby organic molecules (including those important to the survival of microbes, algae, and moss).
Terracyte is sold as a dry granular product that is applied with a drop spreader or other smaller applicator for spot treatments.
The granules must be watered in to activate the oxidizing reaction.
Also, the manufacturer recommends repeat applications within a few days time to get more complete control.
Clover is another weed that has been problematic in bent/Poa fairways this spring.
Common herbicides for control of clover in bentgrass includes application of a three-way phenoxy herbicide product such as Trimec or "bent special," or Confront, which is a mixture of triclopyr and clopyralid.
Unfortunately, phytotoxicity can be a problem with these types of herbicides on bentgrass, even at the low use rates needed to control clover.
However, there is a fairly new product from Dow Agro called LONTREL, which consists solely of clopyralid.
Lontrel has shown very good activity on clover, dandelion, and a few other common broadleaf weeds, while having much less of a ‘phyto’ risk on bentgrass at fairway height.
If yellowing has been a problem for you following phenoxy or Confront applications, you may want to try Lontrel as an alternative clover control (especially as temperatures increase).
Poa annua is in full bloom in northern Illinois, and has probably passed full bloom in central Illinois by now.
Based on my trials this spring, Embark remains the most active growth regulator for suppression of Poa seedheads.
Unfortunately, Embark also causes the most thinning and discoloration of treated bentgrass, even when supplemental chelated Fe was applied.
Turf treated with Proxy (5 oz) or Proxy plus Primo (5 + 1/8 oz) has some noticeable color differences and growth effects, and in most cases has suppressed seeding fairly well (although not as strongly as Embark).
Timing of the first application still appears to be critical, and it seems as though there are some major differences in the response of the various biotypes of Poa annua to Proxy.
Those of you testing Proxy or other seedhead suppression techniques, be sure to drop me an email (rkane@cdga.org) or give me a call (630-257-8126) and let me know how your tests have turned out.
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