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K-State Turfgrass

Orchardrass in Tall Fescue Lawns

By Ward Upham

(Linked from K-State Horticulture e-Newsletter)

Orchardgrass often infests tall fescue lawns. Unfortunately, orchardgrass is lighter green and faster growing than tall fescue, so it is very visible. Homeowners complain of the light green tufts of grass wherever this weed has become established. To read more about this week, visit the website.

 

Iris Leaf Spot: A Common Problem in Kansas

By Judy O’Mara

I was out working in the garden last weekend and I saw the first appearance of iris leaf spot (Didymellina macrospora). This is a very unattractive fungal disease. The iris planting puts out nice looking flowers each year but for the rest of the season everything looks rough, with heavy leaf spotting and leaf scorch. Iris leaf spot will show up in most years but will be severe in years that are wet.

Iris leaf spot is not an easy disease to clean up because it overwinters in the residue. So the first step for management is to clean up the flower bed in the fall after frost has killed the tops. This will help to reduce the amount of disease that is carried over. Unfortunately it won’t get rid of the disease. If the planting is old and crowded, digging them up and respacing them will improve air flow. This can help to reduce disease severity.

Start fungicide protection (chlorothalonil or mycloblutanil) when leaf spotting first shows up early in the spring. Four to six applications may be needed at 7-10 day intervals. Adding a spreader sticker will help coverage and effectiveness of the treatment.

For more information on iris leaf spot check out the following K-State Horticulture fact sheet. https://hnr.k-state.edu/extension/info-center/common-pest-problems/common-pest-problem-new/Iris%20Leaf%20Spot.pdf

Crabgrass Has Emerged

By Dr. Jack Fry

Crabgrass emergence was evident last weekend – at least in Olathe, KS (picture below).

Crabgrass seedlings (inside white border) emerging on April 19, 2020 in Olathe, KS.

 

This was on bare soil next to a paved sidewalk. It can take a few weeks longer for crabgrass to emerge within areas of thin turf due to cooler soil temperatures (see article on timing herbicide applications here: Flowering Ornamentals and Crabgrass Emergence). So, on a lawn of acceptable quality (and no bare areas), you should still have time to get a preemergence herbicide out. Once you see crabgrass such as this emerging within a lawn, consider using a preemergence herbicide that has postemergence activity, such as dithiopyr (Dimension) or mesotrione (Tenacity). Of course, there are also a number of postemergence herbicides that can be used for crabgrass control as well.

Always remember to READ THE LABEL for the correct rate, turfgrass tolerance, and specific instructions before application!!!

***Mention of trade names or commercial products in this article is solely for identification purposes and does not imply recommendation or endorsement, nor is criticism implied of similar products not mentioned by Kansas State University.***

Challenges for Applicators concerning PPE

“This growing season may be a challenge for producers/applicators in more ways than one. With the critical need for N95 respirators for health care workers, it is anticipated that applicators may experience a shortage of personal protective equipment (PPE) that will be available to use this growing season if not previously purchased.”

You can read full article on the KSU Entomology Blog 

 

Progress in Bermudagrass Breeding

By Dr. Jack Fry

This is the time of year when we hope all warm-season grasses green up uniformly with no signs of winter injury.  K-State researchers have been working with Dr. Yanqi Wu, bermudagrass breeder at Oklahoma State University (OSU), for the past several years.  Dr. Wu is consistently working to improve bermuda cold hardiness and release improved cultivars for the transition zone region of the U.S.  ‘Latitude 36’ and ‘Northbridge’, a couple of high quality, vegetatively propagated bermudas, were released by OSU in 2010.  These have been used extensively on sports fields and golf courses.  However, there have been some winters in which significant winter injury occurred to these cultivars in Kansas.  In the article linked below, you’ll see that some of the new bermudas that are being evaluated by OSU and K-State have superior freezing tolerance to any of the existing cultivars in use.  This likely means that in the next several years, we’ll have improved bermudas for our region that will be more likely to tolerate extremely cold winters.
Article here:

https://newprairiepress.org/cgi/viewcontent.cgi?article=7770&context=kaesr

Covid19- no-touch golf, vehicle health/sanitation tips

Hello everyone here are some Covid19 updates that may be useful to your operations.

Please watch for additional information from state and local authorities. As you know, the situation changes daily in terms of case loads, etc.

 

No-touch golf

At present, golf courses in Kansas are open related to policies about “engaging in an outdoor activity.” However, all the rules described in this document must be followed. Click the following link to open the document: 20-16-1 Guidance v2 – Essential Activities Functions

 

Best practices for sharing vehicles

The following document was developed by Colorado State related to farm vehicles but many of the health and safety practices make sense to the “green industry.” Please be sure to watch for any additional guidance or policies from state or local authorities in your area. This is just a general set of practices to consider. You can click for a larger view.

 

 

 

Flowering Ornamentals and Crabgrass Emergence

By Jack Fry and Ward Upham

Efficacy of some preemergence herbicides is strongly dependent upon the timing of application relative to crabgrass emergence.  For example, application of a preemergence herbicide that has a relatively short residual, such as pendimethalin, closer to crabgrass emergence, will extend the period of time which the herbicide is effective.  Herbicides with longer residuals, such as prodiamine (Barricade), are often applied well before crabgrass emergence, and can even be effective if applied late in the previous autumn.

In our climate, calendar dates don’t always adequately identify crabgrass emergence or herbicide application.  Biological indicators, such as flowering ornamentals, may be useful for predicting crabgrass emergence and preemergence herbicide application.

From 1995 to 1997, K-State researchers worked with those at the Univ. of Nebraska to identify ornamentals at each location which best represented crabgrass emergence and preemergence herbicide application time.  Ornamentals evaluated were bridal wreath spirea, callery pear, daffodil, flowering quince, forsythia, iris, lilac, redbud, saucer magnolia, tulip, and vanhoutte spirea.  Obviously, there may be ornamental cultivar differences in blooms, so this was an average of those observed.  In addition, crabgrass can vary in rate of emergence, but getting an herbicide out before the first plants emerge is preferable.  For this article, we’ll focus on results in Kansas.

Crabgrass emergence in bare soil and thin turf was evaluated at the Rocky Ford Research Center in Manhattan. Over three years, the earliest date of crabgrass emergence in bare soil was April 15 1995, whereas the latest date was May 9, 1996.  In the thin turf (10% bare soil evident while standing), the earliest date of emergence was May 5, 1997 and the latest date was May 22, 1995.

Withering of blooms was a better indicator of crabgrass emergence, particularly in thin turf.  In this case, we looked at bloom wither and then compared it to a date 2 weeks prior to emergence.  This 2-week window would allow time for the herbicide to be applied. In Kansas, withering of most ornamentals was not useful for estimating emergence of crabgrass in bare soil, as emergence often occurred before blooms had withered. However, a date 2 weeks prior to  crabgrass emergence in bare soil could be estimated by adding 6 to 12 days to the date of daffodil wither.

Bloom wither of flower ornamentals was used as a date to determine time of application of short-residual preemergence herbicides (a date 2 weeks prior to crabgrass emergence)

 

Flower wither of all ornamentals could be used indicators of emergence (and herbicide application date) in thin turf in Kansas (see Table 1 below). For example, by adding 28 to 33 days to the date of forsythia bloom wither, you will estimate a date 2 weeks prior to crabgrass emergence in thin turf, which would allow time for preemergence herbicide application.  This timeline is quite different from the often used theory that herbicides must be put down at the time forsythia blooms.  Ultimately, biological indicators, along with soil temperatures, will be better indicators of for crabgrass emergence and application of short-residual preemergence herbicides than calendar dates.

Table 1.  Ornamentals and the number of days to be added to flower wither to estimate the date 2 weeks prior to crabgrass emergence in thin turf.  Data were based upon observation of ornamental blooms and crabgrass emergence for a 3-year period.

Ornamental Number of days to add to bloom wither to estimate the date 2 weeks before crabgrass emergence (range allows for standard error)
Bridal wreath spirea 4 to 13
Callery pear 32 to 41
Flowering quince 36 to 42
Forsythia 28 to 33
Iris 8 to 15
Lilac 17 to 22
Redbud 25 to 32
Saucer magnolia 28 to 32
Tulip 21 to 29

 

Note – This article is based upon:

Fry, J., S. Rodie, R. Gaussoin, S. Wiest, W. Upham, and A. Zuk.  2001.  Using flowering ornamentals to guide preemergence herbicide application in the Midwest U.S.  International Turfgrass Society Research Journal.  p. 1009-1012.

The Star-of-Bethlehem makes an appearance….

By Brooke Garcia (Modified original post written by Dr. Jared Hoyle)

Photo taken by Brooke Garcia

Recognize this weed? This time of year, we are beginning to see a lot of star-of-bethlehem popping up in lawns throughout Manhattan, KS. In my neighborhood, which is one of the oldest areas in Manhattan, it seems to be in every lawn. We struggle with this particular weed every year in our turf, as well as our landscape beds.

Photo taken by Brooke Garcia

It is a very pretty plant with showy, 6-petaled white flowers that have a distinct green stripe underneath. It is a perennial bulb that sometime appears to look like clumps of grass. It can be hard to spot in a freshly-fertilized, green lawn. The green hues blend together. The leaves are linear and smooth, flat in cross-section and have a with midrib.

This plant likes shady and moist areas of the lawn, but I have also seen it grow in the sunniest locations of my lawn too. With the recent moisture and more on the way we are not short of moist areas in the lawn around Manhattan right now.

Although it is has very distinctive characteristics it can be confused with other plants that are commonly found in lawns; crowpoison (Nothoscordum bivalve),spring beauty (Claytonia virginica), wild garlic (Allium vineale) and wild onion (Allium canadense).

If you do not have a lot of this weed in your turf or landscape beds, it can be effective to hand-dig the plant and bulb completely out of the affected area. However, the leaves tear quite easily. Thus, it can be difficult to completely eradicate the entire plant using the hand-removal method.

For chemical control there are couple of options.  Both sulfentrazone and carfentrazone have shown to be very effective.

For additional information about Star of Bethlehem, see the recent post written by Ward Upham:

Wild Onion, Wild Garlic, and Star-of-Bethleham

***Mention of trade names or commercial products in this article is solely for identification purposes and does not imply recommendation or endorsement, nor is criticism implied of similar products not mentioned by Kansas State University.***