some dollar spot info, and another new tree disease

It is hard to believe that there are only a few more days in September.

It is pretty quiet on the disease front. Dollar spot and large patch are the major issues.

First, I have to correct a typo from last time. I had listed a dollar spot fungicide treatment with Trinity as 0.1 oz/1000 and in fact it was 1.0. Apologies for any confusion.

Posted below are treatments from another dollar spot study that was conducted in a stand of A4 at our research center in Manhattan. I had a figure ready to go, pasted it, but then when I actually uploaded it turned to gibberish. Then, did it again. So I'll just type in a summary of the information:

All treatments were applied on a 14-day interval at 2 gal/1000


TREATMENTS & OZ/1000
1) untreated
2) Triton Flo, 0.5
3) Triton Flo, 0.75
4) Triton Flo, 1.0
5) Banner Maxx, 2.0
6) Reserve, 2.8
7) Reserve, 3.2
8) Reserve, 3.6
9) Reserve, 4.5
10) Concert, 5.0

On August 27 and Sept 10 the % dollar spot in the untreated plots was 9 and 15%, respectively. On Aug 27th, all the fungicides held dollar spot to zero. On 10 September, Banner Maxx, Concert, and Reserve at the 3.6 oz rate held dollar spot to zero, and the others all had just traces of disease, no more than 1% plot damage.


New disease on black walnut:

I know this is a turf blog but I also work with trees and ornamentals and I have sneaked in some tree stuff here before. If you don't care about trees, just skip it, but I do get a lot of questions about trees & ornamentals in golf courses so thought I'd pass in this news.

Dutch elm disease, chestnut blight, emerald ash borer, Asian longhorn beetle, sudden oak death... You might have heard of some of these tree diseases and insect pests.

There are always new problems arising to threaten our tree resources.

There is a new insect-fungus complex killing lots of black walnut trees in Colorado.
(I also know that a few folks consider black walnut a pesky tree because of the mess made by the nuts, but it is also a valued landscape tree in many sites, as well as an important part of native forests in the eastern half of the US).

Plant pathologist Ned Tisserat (formerly at K-State, now at Colorado State) and entomologist Whitney Cranshaw (Colorado State) have been working on this disease, and this past week representatives from other states in the region were in Denver to see the disease first-hand, learn about the biology and current research, and practice diagnosing it in the field.

There was a contingent of 7 from Kansas (yours truly and one more from KSU, three from the KS Forest Service, and two from the Kansas Department of Agriculture) who attended.

I took numerous photos and tried to post some here but, like with my dollar spot figure, I kept getting weird errors. D'oh! There are pics available in the link below.

The Colorado team showed us black walnuts in various stages of decline, then at two sites we had the opportunity to cut into several felled trees to look for the tiny beetles (adults and larvae were present), the canker symptoms, and the fungus. As we all know, there’s nothing better than field experience to really learn about a new disease or insect.

In Colorado, black walnut is only in landscape plantings. Here in Kansas and in other states up and down the plains we have both landscape and native black walnut, and we also have an important walnut timber industry. Regional plans are evolving to try to prevent spread of the disease, and to deal with the disease if it does appear in new states.

For more information about this disease, and photos, you can visit this website:

http://www.ext.colostate.edu/pubs/insect/0812_alert.pdf