Bermudagrass Winterkill Again?

Some are suffering through another year of bermudagrass winterkill in Indiana. Much different than last year where winterkill was widespread and there were many different causes (too cold, too wet, too shaded, etc.), the primary cause for winterkill in 2014-2015 in Indiana appears to be confined to immature bermudagrass. Those that were not able to replant in 2014 until after July 1 or those whose bermudagrass recovered very little in 2014 seem to be hit the hardest. As such, we encourage all those who anticipate planting or replanting bermudagrass in 2015 to try and plant this month (June) to increase the odds of their bermudagrass surviving the 2015-2106 winter.

We are continuing to examine the cold hardiness of various bermudagrass cultivars. Our bermudagrass research plots at Purdue were almost entirely killed this past winter with only one entry, Yukon, seeming to do well thus far. All others were severely injured and we are in the process of reestablishing these bermudagrass plots to try and learn more about the adaptation of certain bermudagrass cultivars to the Midwest. Stay tuned for more results as they become available.


For more information on bermudagrass winterkill, see these previous turf tips.
Warm-season Turf Winterkill 2014: What Can you Expect and NOW WHAT? (March 12, 2014)
Winterkill Here on Bermudagrass! Now What? (June 27, 2014)


For more information regarding bermudagrass winterkill on the east coast this year, read these recent postings.
Winterkill of Bermudagrass in North Carolina
Winterkill hits Carolinas

Aaron Patton and Cale Bigelow
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Weed of the Month for May 2015 is Orchardgrass

Biology: Orchardgrass (Dactylis glomerata), is a clump-forming, or bunch-type, cool-season grassy weed found throughout the Midwestern United States. It is typically used as a type of grazing or forage grass in pastures but it can be a weed in turf. It’s bunch-type growth pattern, light blue-greenish color, ability to tolerate partial shade, and rapid leaf elongation make orchardgrass a problematic weed (plant out of place) in many lawns.

Identification: Orchardgrass is a bunch-type cool season perennial grass that is commonly found in home lawns throughout the state of Indiana. Orchardgrass often infests lawns as a contaminant in grass seed or in newly established lawns that previously consisted of pasture-land. Orchardgrass can often be found thriving in partially shady conditions that might stress the health of the surrounding, desirable turf. It is easily spotted in lawns when it grows much more quickly and is lighter-green the surrounding turf. Additionally, its bunch-type growth habit doesn’t make a particularly dense canopy when it infests lawns, thus only enhancing its status as a grassy weed.

Its leaves are folded in the bud and have a finely toothed, prominent membranous ligule. As it grows, the leaf blades become very long, are light-green/blue-green in color, and are still slightly rough to the touch on the surface and the outer leaf margins. The membranous ligules grow slightly longer and become more noticeable as the plant matures. The leaf sheaths are strongly compressed and folded. Because orchardgrass has a bunch-type growth habit, the clumps increase in size by developing aggressive tillers which emerge from the base crown of the plant. Orchardgrass also has a very rapid vertical growing rate compared to other desirable cool-season turf which requires more frequent mowing in order to keep a uniform lawn surface. Additionally, the leaf tips have a tendency to tear or shred, even when the mower blades are sharp.

 In the late spring through mid-summer, the plant produces seedheads in a stiff, branched panicle with fan-shaped, densely crowded spikelets of viable seed. The spikelets are often so crowded that when observed from afar, the seedhead almost looks globular or spherical in appearance.  

The prominent membranous ligule of orchardgrass.


A side view showing the compressed sheath/stem and folded vernation.

Orchardgrass has a boat-shaped leaf tip.

Clump of orchadgrass in a shady lawn.

Clump of orchadgrass in a newly seeded Kentucky bluegrass lawn.

Orchardgrass in a newly planted Kentucky bluegrass sod field.

The faster growth habit of orchardgrass is evident here.

Here a mature clump of orchardgrass is growing much quicker than the surrounding turf species.

Orchardgrass seedhead developing in a lawn between mowings.

Cultural control: None known specifically for orchardgrass. Mowing practices alone will not provide adequate management since orchardgrass can survive in many of the same environmental conditions and management programs as other desired turfgrass species. The best method of cultural control for orchardgrass is to avoid contaminating your turf system in the first place by buying certified seed mixtures/blends from a reputable seed company. Carefully read the labels of seed you are purchasing to make sure that orchardgrass is not mentioned as a weed seed. Existing clumps of orchardgrass can also be physically removed by hand, pocket knife or shovel/hoe.

Biological control: None known specifically for control of orchardgrass in cool-season lawns.

Chemical control: Unfortunately, only nonselective control options exist for orchardgrass in cool-season turf. Spot-treating with a nonselective systemic herbicide such as glyphosate (Roundup) will help to manage orchardgrass in cool-season lawns. For best results, apply when the plants are young and actively growing. Often multiple applications may be necessary to completely eradicate the weed; however, it is important to allow the grass to regrow before making any follow-up applications.


For more information on weed control, search this blog and check out our Turfgrass Weed Control for Professionals Publication.

For archives of past weed of the month postings, visit our Weed of the Month Archive.

Aaron Patton, Turfgrass Extension Specialist, Purdue University

Leslie Beck, Weed Extension Specialist, New Mexico State University
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Rounds 4 Research: Auction is Open! Support the Purdue Turf Program

The 2015 Rounds 4 Research auction is now open. The auction will run from June 8 to June 21 with proceeds going to support turf research at Purdue and in Indiana through the Midwest Regional Turf Foundation, advocacy and education programs for the benefit of golf course management professionals, golf facilities and the game.


This fundraiser offers great golf deals and access to exclusive golf courses in Indiana and the nation. 33 foursomes were donated in all in Indiana. So, tell your friends, family, and community to bid on these rounds. Let the bidding begin!

Bid Online Now (https://www.biddingforgood.com/auction/auctionhome.action?vhost=eifg)
 

If you have any questions, please contact the Rounds 4 Research team at mwright@gcsaa.org or 800-472-7878.

Thank you for your support!



Aaron Patton, MRTF Executive Director
Ryan Cummings, Elcona Country Club Golf Course Superintendent and MRTF Rounds 4 Research Coordinator
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Is it Safe to Aerify after Applying a Preemergence Herbicide?


It is not uncommon for me to receive questions regarding whether it is OK to aerify an area when you’ve already applied a preemergence herbicide to control crabgrass. Will aerifying break the herbicide barrier and reduce my crabgrass control? The answer to this and more can be found here in a recent post I wrote at Turf Republic.

To Aerify or Not to Aerify when Using a Preemergence Herbicide




Aaron Patton, Turfgrass Extension Specialist
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European Chafer Causing Serious Damage in Northeastern Indiana


Although reports of spring white grub damage have been relatively uncommon in Indiana in recent years, there have been a growing number of cases in the northeastern part of the state.
The European chafer Rhizotrogus majalis Razoumowsky is apparently at the root of several reports of large scale and severe damage to turfgrass this spring. This insect is a slightly different beast than our more familiar white grub species. It is significantly more cold-hardy which allows it to feed later into the fall and start feeding earlier in the spring compared to Japanese beetle and masked chafer grubs. It also shows up in areas with no previous history of white grub damage, including low maintenance areas.

Folks in Michigan have been dealing with this insect for many years now, but it is relatively new to Indiana; adults of this species were first detected in Porter, Kosciusko and Allen counties during 2007. With the help of several diligent individuals in the green industry, we have now linked several reports of serious spring white grub damage in LaGrange, Noble and Elkhart counties to this insect meaning that populations are now established in these areas and are likely established throughout the northern third of the state (see Figure 1 and 2).

Figure 1. Home Lawn in Nobel County showing extensive damage from European chafer grubs.

Figure 2. Low maintenance turf area showing patchy damage from European chafer.


Spring grub control can be difficult to achieve and the only realistic chemical options are trichlorfon or carbaryl. Even then, repeated application may be necessary and damage is not likely to be reversed at this late time. A more proactive approach aimed at preventing infestation this summer is more likely to provide a reasonable solution. Recommended products and application timings for white grub control can be found here: http://extension.entm.purdue.edu/publications/E-259.pdf. European chafers may also cause damage to a variety of field, forage and grain crops (see Figure 3).


Figure 3. Extensive, but patchy damage to winter wheat caused by European chafer grubs.


If you notice grub damage this time of year, take a closer look and try to find the larvae in the soil. European chafer larvae can easily be identified using a 10X hand lens to inspect the raster pattern (Figure 4). Once established these insects may require some special attention going forward as they tend to be more damaging and somewhat less vulnerable to traditional insecticide treatments. The best control is achieved using a preventive approach with applications of imidacloprid, thiamethoxam, clothianidin or chlorantraniliprole applied June through mid-July. Keep records of any European chafer infestation in order to identify areas to keep an eye on going forward.


Figure 4. Location (A) and form (B) of the raster pattern in European chafer grubs.

Doug Richmond, Turfgrass Entomologist and Extension Specialist
Email: drichmond@purdue.edu

Follow me on Twitter @doctorDRich

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Hunting Billbug Larvae Overwintering in Indiana


We recently discovered that the hunting billbug is capable of successfully overwintering in the larval stage as far north as West Lafayette Indiana. This insect is mainly a pest of warm-season turfgrasses such as Bermudagrass and zoysiagrass and has become a perennial problem in parts of the state where these grasses are cultured. Although we’ve known for several years that this insect overwinters as an adult and produces two generations per year in this part of the country, its ability to overwinter here in the larval stage was previously unknown. Overwintered adults have been the primary management target, but insecticide applications targeting adults may have little impact on the soil-dwelling larvae. Instead of just 2 generations to think about, managers should be aware that 2 separate cohorts may occur.


Figure 1. Hunting billbug larvae found in soil during March 2015.

Figure 2. Hunting billbug adult (actual size = approximately 1 cm).

Figure 3. High- (top) and low- (bottom) cut zoysiagrass damaged by hunting billbug.




This means is that both larvae and adults may be active and present over much of the growing season. This fact could complicate insecticide timing, narrow the spectrum of useful management options and spread damage over a larger portion of the growing season. The following table contains chemical management recommendations based on my experience and those of our colleagues in North Carolina who have been dealing with this exact issue for some time.

Table 1. Chemical management options for hunting billbug based on target stage of the insect.

Target Stage(s)		 Active Ingredients Timing
Adults bifenthrin, deltamethrin, lambda-cyhalothrin, zeta-cypermethrin As soon as adults become active (late April – early May)
Larvae clothianidin, thiamethoxam, imidacloprid, chlorantraniliprole When larvae are inside stems or crowns or present in soil
Adults &
Larvae		 clothianidin + bifenthrin (Aloft), imidacloprid + bifenthrin (Allectus)
bifenthrin + zeta cypermethrin + imidacloprid (Triple Crown)		 When adults and larvae are present or after adults have been active for several weeks
Always follow label directions and recommended application rates


by Doug Richmond and Alexandra Duffy, Department of Entomology, Purdue University
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Weed of the month for April 2015 is Smooth Crabgrass

Smooth Crabgrass  

Biology: Smooth crabgrass (Digitaria ischaemum), is a summer annual grassy weed that is found throughout the Midwestern United states. Closely related to large crabgrass (Digitaria sanguinalis) and southern crabgrass (Digitaria ciliaris), these three species are often considered to be the most problematic weeds in lawns due to their ability to survive extremely low mowing heights, poor quality soils, and dry/hot climates.

Identification: Smooth crabgrass is a summer annual grassy weed that is commonly found in home lawns throughout the US. Smooth crabgrass can tolerate very dry, poor quality soils and is found in multiple cropping systems ranging from agronomics, to landscape, to horticulture, to vegetable gardens, along with both cool and warm season lawns in Indiana. Crabgrass plants are very opportunistic, so look for it to germinate in areas of bare soil like walkways, gardens, newly seeded turf areas, as well as a very open, thin turfgrass canopy.



Germination typically occurs from mid- to late-spring (late March-early May) in Indiana. If germination occurs while the temperatures are still slightly cooler, the plant will remain small for an extended amount of time. As the temperatures warm, more leaves will start to develop and the plant will begin tillering by early- to mid-summer (June). The young leaves of smooth crabgrass will have very little hairs, while large and southern crabgrasses have a dense covering of very fine hairs. All three crabgrass varieties will have a membranous ligule that has a torn or ‘shredded’ appearance.

Smooth crabgrass leaf emerging from coleoptile.

1-leaf size smooth crabgrass.

2-leaf size smooth crabgrass.

3-leaf size smooth crabgrass.

Usually some hairs are present on smooth crabgrass but many fewer than on large crabgrass.

Photo shows membranous ligule and few hairs on leaf sheath or leaf blade.


The development of multiple tillers can contribute to the clumpy appearance of a crabgrass plant, though smooth crabgrass is generally smaller in size than large crabgrass. Once mature, smooth crabgrass produces seedheads in the form of 3-5 spikes that are clustered at the top of long, erect stems. Seedheads mature at the end of summer prior to fall/autumn. As crabgrass dies with the first killing frost, the plant can appear as unsightly brown patches surrounded by green cool-season turf in lawns.



Prostrate growth of smooth crabgrass in short cut turfgrass.

Dense turf keeps out crabgrass. Here a patch of creeping bentgrass in a lawn is keeping out the crabgrass.


Chilling injury to crabgrass in cool fall months prior to the first frost.

Brown, dead crabgrass plants in a lawn following the first hard frost.

Cultural control: Maintaining a high quality lawn through higher mowing heights, proper fertilization (some fertilization is always better than none), and supplemental irrigation during drought will help the desired turf to outcompete crabgrass.

Biological control: None known specifically for control of smooth crabgrass in home lawns.

Chemical control: For more information about crabgrass control, see our recent post, Common Questions About Crabgrass Germination and Preemergence Herbicides Answered.

Both smooth and large crabgrass can be controlled using preemergence and postemergence herbicides.

There are multiple options for preemergence herbicides that are available for purchase by homeowners, including dithiopyr (Dimension), pendimethalin (Pendulum), and prodiamine (Barricade). These herbicides prevent the crabgrass from successfully germinating. For adequate control, these products must be applied before the crabgrass starts to germinate. One exception is dithiopyr, which has the ability to control crabgrass after it germinates until it reaches 1- to 2-tillers in size.

Once the crabgrass has already emerged, another option for control is the use of postemergence herbicides. Products that include active ingredients like dithiopyr (smaller than 1- to 2-tiller in size), quinclorac (Drive), mesotrione (Tenacity), fenoxaprop (Acclaim Extra) can be used to adequately control crabgrass that has already emerged. Each of these individual fertilizers provide a slightly different spectrum of control and works well on specific sizes (based on number of tillers) of crabgrass. Homeowners can choose a product based on the size of their crabgrass as well as its ability to control other weeds that you might have present.


For more information on weed control, search this blog and check out our Turfgrass Weed Control for Professionals Publication.

For archives of past weed of the month postings, visit our Weed of the Month Archive.

Aaron Patton, Turfgrass Extension Specialist, Purdue University
Leslie Beck, Weed Extension Specialist, New Mexico State University
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