Greens and Goosegrass

I thought I would talk about our biggest weed issue, not because we have more goosegrass on greens compared to other areas, (although some years it might seem like it), but goosegrass is more problematic on putting surfaces.  As the photos below show, how problematic goosegrass can be on putting greens.


This picture was taken in 2015 on our fifth green in August of that year.  August has been typical of the time we start seeing goosegrass in greens.  Not all greens will have it, and some that do will have varying degrees of it.  (Some of the color seems a little off because I blew the picture up some and also due to I think some clouds that day.)






This is from our chipping green this past September of 2017.  We did start seeing breakthrough of goose in August of this past year as well.

Our 10th green is the green I actually will watch for goosegrass to emerge first.  Some seasons it might be the only green that will have goosegrass, along with a few heavily traffic areas on greens.  Other seasons the goose is a little more widespread.



I think why 10 green sees more goosegrass could be for some reason it tends to dry out a little quicker than many of our other greens.  It was constructed in a different time frame, and could have maybe a little bit different particle size greens mix than other greens.  It is also possible the greens mix itself might be a little deeper causing the perched water table to be deeper and allowing the green to dry out quicker.  All which causes the green to be watered more and we wonder if that is breaking down the preemergent application?  When talking with other superintendents, they seem to have more problems with goosegrass during very wet seasons.  This past season we saw 15.49" of rain in April, 8.8" in May, 8.03" in June, and 7.39" of rain in August.  Well above normal.  In 2015, the picture of # 5 green came from, we had 8" of rain in May, 6.6" in June, 8.35" in July, and 7.36" in August.  (All information from data collecting).

The pre-emergent product we have been using for quite awhile (I would say 10+ years) is dithiopyr in a fertilizer combination.  Prior to last year it was a 0-0-20 w/.162% dithiopyr which we would apply in 2 split applications.  The first one pretty much two weeks after our spring greens aeration, which would be somewhere around the 15th of April.  We were pretty darn consistent with this application, only missing the target date by a day or two if we missed at all.  The follow up application would occur usually 6 weeks later, shooting for the last week of May.  If we missed this date, we could be a week or two behind for that second application.  I have to wonder, was that part of the cause of my problem?  Last year we switched to a different product, same active ingredient of dithiopyr.  We went with a 0-0-5 with .103% dithiopyr and followed a highly used program timing in our area.  We still made that first application on the second week of April, we made the second application three weeks later, with the last application three weeks after that, (same timing as our second application of the 0-0-20 product)  We still came up with some goosegrass in August.  Was it the 32+" of rain in April, May and June?  Or was it possible that I missed the first application date?  Goosegrass will germinate when soil temperature averages stay in the 60-65 range at 2" depths.  While I regularly check soil temperatures, could I have missed my window due to checking a soil temperature during the cool early morning, or when I might have missed taking the soil temperature while doing one of my many other chores, or those couple of days off?  Did both issues play a part?  (My philosophy is it usually isn't just one thing that causes an issue).  This year I am committing myself to not miss that soil temperature window.

We will again go with the 0-0-5 with .103% dithiopyr with the same 3 split applications.  Two exceptions will be on # 10 green I will do two split applications of another product that contains Bensulide and Oxadiazon, and I will split the practice green up into fourths, with the 0-0-5 being applied to two areas, and the Bensulide and Oxadiazon being applied to the other two locations.  The other reason I am using four sections of the practice green is there will be two fertilizer trials going on as well.

So how will we attack any goosegrass that has emerged?  We will continue to pull some of the plants we see during course setup and while mowing.  As the pictures below show, these are some tough weeds, but fairly easy to pull with the right tools, and if they get a little large on us.

       

 One of the other tricks we have tried with some success is loading up a plastic tube that has a sponge on the bottom, with chemicals and dabbing that chemical onto the goosegrass plant.  As the picture to the right indicates.  We have used MSMA because it works great on goosegrass, it is very cheap, and we can still use it on the golf course in small settings by spot applying.  The problem we had with using MSMA, was any MSMA that touched the bentgrass next to the goosegrass was killed as well, leaving the areas we treated with small dead spots, visually unappealing.  Unfortunately I did not get some good pictures of the results.  

Our other chemical option we will try this next season is using the herbicide Pylex.  We did some trials with Pylex this last season, all in our large turf sprayer.  I am going to dedicate another blog to the whole process of trying the Pylex, as it has a variety of uses, and we sprayed a variety of areas with it.  The area in this blog that I will show is the back of our chipping green.  I mixed the Pylex at a rate of 1/2 oz per acre.  The results are shown to the right.  Some of the classic ghosting signs are in the picture, this is the results of using the Pylex.  I have seen some people use the Pylex in dobber tools with good results.  The toughest part is mixing the small amount of product (.032 oz per gallon or 1 ml for my Canadian friends, I guess the metric system can be handy).  It is best suggested to mix that small amount of product in about 8 oz of water then add it to the backpack sprayer or dobber.   

This is an ongoing project to find the best solutions to the issue of goosegrass on our greens. 

I am hoping to talk in a future post about how we have worked to control goosegrass on tees and fairway areas.  What we have tried, how well it has worked, and how we look to go forward in that issue.  Looking at both pre and post emergent herbicides.

If anyone wants to share their successful programs, or see how we can make some improvements to our current programs, I hope you will share your secrets.

Thanks for reading!

Mel