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Frequent rains and moderate temperatures this past week seems more like weather we should get in late May instead of late June (summer is officially here!).
I have found very little new pest activity in relation to last week's update.
It is almost too quiet (especially on the insect front).
Most of the dollar spot seems to be laying low for now (how about central IL?).
However, if it keeps raining and warms up a bit, leaching of N will occur and the lower fertility will give the dollar spot fungi an advantage.
Diseases
Take-all patch on bent grass continues to be the disease of concern for now, especially on newer golf courses or recently renovated areas.
Keep in mind however that we have seen take-all on older golf courses (esp. fairways), but it is usually less of a problem on well established turfs.
Take-all symptoms can be confused with Rhizoc. brown patch or localized dry spot, but weather conditions haven't favored either problem in northern Illinois (especially dry spots!!!) Preventive fungicide treatment of take-all can be a very expensive proposition, especially on newer courses with large fairway acreage.
Many have suggested "spot" treatments for take-all as a lower cost alternative, either preventative spot treatments on areas you know the disease will show up (eg front half of a tee), or curative treatments on active disease (eg individual patch treatments).
I have tried curative spot treatments in the past by mixing small amounts of fungicide in a hand sprayer and drenching individual patches -- with mixed success.
This type of treatment with Heritage, Rubigan, or Cleary 3336 may help reduce symptom severity and promote healing and recovery once the disease is inactive.
(You must be careful when drenching a DMI fungicide such as Rubigan because of the potential PGR activity.)
There is research underway at many universities to find alternatives to fungicide control for take-all -- such as different fertility programs (cultural control) and antagonistic bacteria (biocontrol).
Other diseases to watch for in upcoming weeks: anthracnose on Poa annua may fire up soon with all of this rain; Pythium and brown patch should be a concern if hot weather moves in?
Insects
I have seen/heard of very little in the way of insect activity on turf, since the reports in late May of cutworms and overwintering grubs.
Has anyone seen any Black Turfgrass Ataenius adults? Let me know if you have, I have yet to see my first adult wandering around on a green? Ants remain a big problem on greens.
Has anyone tried the new, slower acting baits such as Maxforce?
Again, let me know on email if you what you have tried and how it worked out? For news on insects and other pests of trees and ornamentals, check out the U of I home yard and garden newsletter:
http://www.ag.uiuc.edu/cespubs/hyg
Weeds
Here is a brief review of my Poa annua seedhead suppression study (in cooperation with Bruce Branham at the U of I and generously funded by USGA - thanks Paul!)? I wanted to study the activity of the old wetting agent called Aqua-Gro L, which has been used for many years in early spring to reduce Poa seeding on greens.
Aqua-Gro is now longer in production, so I also wanted to look at alternatives -- both in terms of comparative efficacy and safety.
Aqua-Gro can cause a mild tip burn, but is usually not noticeable in early spring apps.
Alternatives I applied included: Embark, Primo, Proxy, and Enhancer (all PGRs of various sorts), and Cascade (a wetting agent).
Cascade has been tried recently as a substitute for Aqua-Gro in some locales - so far with moderate success reported.
The applications were started in mid-April, around the time that Poa started to show seedheads.
But the timing was difficult to determine this year because of the unusually warm weather we had during winter and early spring.
If Poa seeding is based on soil and air temps, the timing could have been thrown way off this year! Also note that I applied all of the PGRs in the same time frame as the wetting agents, which may or may not be the best way to use some of these products for Poa seedhead suppression.
So far, the results of the applications have been mixed, but I did get really good long-term seedhead suppression with Embark and Proxy.
Embark is the old standby product for seedhead suppression, but many choose not to use it because: 1) timing of applications can be very critical for success, 2) yellowing and other phytotoxicity problems are common, especially where overlaps or other misapplications occur.
Because of the latter concerns, Embark is now formulated in a much more dilute concentration (called Embark T & O).
The Proxy results were a total surprise, although I had heard of a few studies where Proxy had worked for Poa seedheads.
Unfortunately, the Proxy rates I applied caused some thinning and yellowing of treated plots, so I will have to adjust the application rates and try again next year.
I will publish all of the application rates, dates and results in On Course later this summer.
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