Lawns and Turf

Do you recognize this large wasp found in landscapes now?

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Cicada Killer Wasps

Nancy Hinkle, UGA Extension Entomologist

Cicada killer - Jessica Lawrence, NC State Entomology Department, Bugwood.org
Cicada killer – Jessica Lawrence, NC State Entomology Department, Bugwood.org

The cicada killer wasp is the largest wasp in Georgia. The cicada killer wasp is almost two inches long. Although intimidating in appearance, these wasps are not something we humans have to worry about. Cicadas, on the other hand, should be very afraid. Cicada killer wasp adults feed on nectar but use paralyzed cicadas to feed their young.

Female cicada killers are hard to provoke to sting.  The female uses her stinger to paralyze her prey (cicadas) rather than in self defense. The female’s attention is focused on providing food for her babies, so she poses little threat to humans.

Cicada killers prefer to nest in sandy open sunlit areas.  As the female digs, she kicks out soil that forms a semicircle around the burrow opening. She burrows six to ten inches into the ground, prepares a chamber, catches a cicada to fill the chamber, lays an egg on the cicada, and seals the chamber.  She may do this over a dozen times in one burrow.

Cicada-killer-Ronald-F.-Billings-Texas-Forest-Service-Bugwood.org_-300x200
Cicada killer – Ronald F. Billings, Texas Forest Service, Bugwood.org

When a female finds a cicada, she paralyzes it with her stinger, straddles it, and attempts to fly with it to her burrow.  Because the cicada typically weighs more than she does, these flights are usually hops, with more dragging than gliding.

The egg hatches in a few days and the larva feeds on the paralyzed cicada until nothing is left but a shell. Then the wasp larva pupates within the burrow, remaining there until the next spring.

Males cannot sting; their only defense is intimidation.  They patrol the nesting area, trying to divert attention away from the female, allowing her to provision her nest with cicadas.  Meanwhile the male is using threatening tactics to distract potential predators. He may even dive bomb perceived threats.  Since the males do not have stingers, they are completely harmless.  They must rely on bluff, bluster, and bravado to protect their families.

Because cicada egg laying can be damaging to trees and shrubs, cicada killer wasps are very beneficial, providing free biological control.  However, homeowners who do not want these wasps around can modify their lawn to be unappealing.  A thick healthy turf with no bare spots will exclude cicada killer wasps. If turf is thin in nesting areas, identify turf problems that make the turf weak and correct them.

Cicada killer wasps will be active for only a few weeks and will be gone by mid-August in most of Georgia. If someone is bothered by these wasps, late July and early August would be a good time to take their vacation.

For more on cicada killer wasps, see these articles:

Giant wasps not after humans

Killer wasps swarm in August

Prevent White Grubs Now

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Will Hudson, UGA Extension Entomologist

White grub eggs and small larvae
White grub eggs and small larvae

June and July are excellent times to prevent white grubs in turf. White grubs live in the soil and feed on the roots of turf. Most white grubs have a one year life cycle in Georgia. Adult beetles lay eggs in late spring or early summer. The eggs hatch into grubs which feed and grow through the summer and fall, then dig down to spend the winter deep in the soil. They become active as the soil warms in the spring, and feed for a few days to a few weeks, depending on the species. They then turn into pupae before emerging as adult beetles to continue the cycle.

White grub larvae
White grub larvae

White grubs are the immature stage of Scarab beetles like green June beetles, Japanese beetles, chafers and others. The scarabs are a large family of beetles, and there are perhaps two dozen different species of white grub that might be found feeding on the roots of turf in Georgia. Included in this group are some of the most serious insect pests a turf manager will face.

White grubs damage turf by feeding on the roots during the summer and fall and, to a lesser extent, in the spring before pupation. Very dry conditions can reduce survival of both eggs and small grubs.

White grub injury on turf
White grub injury on turf

Symptoms of white grub damage are similar to other factors that damage the root system – disease, soil compaction, poor fertility, or drought. Except for the green June beetle, grubs never come to the surface until they become adults. The only way to tell if a lawn is infested is to dig the grubs up.

To scout for white grubs, cut 3 sides of a square of turf and lay the grass back like a carpet. Dig gently in the soil to a depth of 4 inches and count the grubs you see. It is important to identify the grubs before you treat. The potential for turf damage is dependent on the number and types of white grubs present. Your county agent can help identify grubs or see the publication White Grub Pests of Turfgrass on the CAES Entomology Department website.

It is easiest to find white grubs in early spring and late summer (late August) when they are larger and easy to see. That is not the best time to treat, however. Treatments are more effective if applied while grubs are small. In most of Georgia, this means application in June or July for best control. Once white grubs get bigger, there are fewer effective options and higher pesticide rates will be required. Good soil moisture and watering in the pesticide is also important for white grub control.

See White Grubs of Turfgrass for good information on control measures. Consult the Georgia Pest Management Handbook for current pesticide recommendations. Follow all label recommendations when using any pesticide.

What is this common problem of centipede lawns?

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Centipedegrass Decline

Alfredo Martinez, Extension Plant Pathologist and Clint Waltz, Extension Turfgrass Specialist
Adapted from original manuscript prepared by Drs. E.A. Brown, Retired UGA Extension Plant Pathologist and G. Landry, Retired UGA Extension Agronomist

Failure to green-up in the spring or successful green-up followed by decline and death in late spring and summer is a problem that can be encountered in centipedegrass-growing areas. Centipedegrass is subject to a condition called “centipedegrass decline.”

Many factors may contribute to this problem. It is important to be aware of these factors so that preventive and/or corrective steps can be taken. This problem can be prevented by proper management, which includes avoiding over-fertilization, preventing thatch accumulation, irrigating during drought stress (particularly in the fall), and maintaining a mowing height of 1 to 1.5 inches.

See the entire Centipedegrass Decline publication or read these sections:

Lawn and Garden Moisture Index

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Information taken from the Climate and Agriculture in the Southeast (CASE) newsletter.

Do things seem really dry where you are?  How much should you water your lawn or irrigate your crops?  There are a number of commercial products out there that can help you determine this, but one simple method that is available for free is the Lawn and Garden Moisture Index, a daily map put out by the Alabama State Climatologist based on estimated rainfall from radar.  This map tells you whether your lawn and garden have enough moisture or if more needs to be added.  This is one of a number of useful products available on AgroClimate.org, a website developed by the Southeast Climate Consortium, a group of eight universities around the Southeast.

lawn-garden-7-8-2014-235x300

This map shows the areas with surplus water in greens (no need to water or irrigate there) and areas with a water deficit in oranges and reds.  The darkest red areas are almost 2 inches short of water, including a large portion of Georgia.  If this situation continues, then the Drought Monitor is likely to add D0, abnormally dry conditions, to the next weekly Drought Monitor map.  Areas with deficits of an inch or more should be irrigated to help alleviate the dry conditions and keep lawns and gardens healthy.

What is this weed and how do we control it?

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Lespedeza McCullough
Common lespedeza in a centipedegrass lawn. Photo by Patrick McCullough.

This weed is common lespedeza. To learn about is biology and control, see this publication by Patrick McCullough, UGA Extension Weed Specialist. This information is taken from his publication.

Common lespedeza (Kummerowia striata (Thunb.) Schind syn. Lespedeza striata) is a freely-branched summer annual legume that is a problem weed in lawns and other turf areas. Common lespedeza, also known as Japanese clover or annual lespedeza, has three smooth, oblong leaflets with parallel veins that are nearly perpendicular to the midvein

Common lespedeza woody stems in late summer. Photo by P. McCullough.
Common lespedeza woody stems in late summer. Photo by P. McCullough.

As common lespedeza matures, the stems harden and become woody, which is attributed to persistence and competition with turfgrasses in late summer

Flowers are pink to purple and present in the leaf axils. Other lespedeza species may also be found as weeds in turf but common lespedeza is the primary species in Georgia.

Leaf of common lespedeza. Photo by Patrick McCullough
Leaf of common lespedeza. Photo by Patrick McCullough

This publication gives information on

To see the entire publication click here.

Find other UGA publications here

An unusual lawn invader appears during wet weather

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Slime mold 3 turf disease pubThis is a Slime Mold growing on turf.

This information is taken from the UGA publication, Turfgrass Diseases in Georgia: Identification and Control 

Slime molds are caused by the fungi Physarum spp. and Fuligo spp.

All turfgrasses are susceptible to slime molds

Slime mold turf disease pubSymptoms: Large numbers of pinhead-sized fruiting bodies may suddenly appear on grass blades and stems in circular to irregular patches 1-30 inches in diameter. Affected patches of grass do not normally die or turn yellow and signs of the fungi usually disappear within 1 to 2 weeks. These fungi normally reproduce in the same location each year. The fungi are not parasitic, but they may shade the individual grass leaves to the extent that leaves may be weakened by inefficient photosynthesis.

Conditions favoring Slime Molds: Slime molds are favored by cool temperatures and continuous high humidity. An abundance of thatch favors slime molds by providing food directly in the form of organic matter.

Management:

Remove slime mold by mowing.

Remove using a gardening tool or high pressure stream of water.

For more information on slime molds and other turf diseases, see Turfgrass Diseases in Georgia: Identification and Control 

 

Slime molds elsewhere:

Dog vomit slime mold, Sandra Jensen, Cornell University
Dog vomit slime mold, Sandra Jensen, Cornell University

Other slime molds form irregularly shaped ‘blobs’ that grow on mulch, turf or other areas with organic matter. Read more about these in the publication, The Truth about Slime Molds, Spanish Moss, Lichens and Mistletoe

 

Also find pictures of various slime molds here.

Can you identify and control this troublesome weed?

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Info taken from the publication Virginia Buttonweed Identification and Control in Turfgrass by Patrick McCullough and Jialin Yu, UGA Department of Crop and Soil Sciences

Virginia buttonweed (Diodia virginiana L.) is a troublesome broadleaf weed in turfgrass throughout the southeastern United States. Virginia buttonweed is a deep-rooted perennial with prostrate or spreading branches. It usually proliferates in moist to wet areas and can tolerate mowing heights as low as one-half inch. The species is a member of the Rubiaceae family and is found from New Jersey, west to Missouri and south into the Gulf Coast states.

Virginia buttonweed leaves are slightly thickened, opposite without petioles and slightly rough along the margins (Picture 1). Leaves are green on the upper surface, light green on the lower surface and often have a mottled yellow mosaic appearance caused by a virus that commonly infects foliage (Picture 2). Branched stems are occasionally hairy (Picture 3) and reproduction occurs via seeds, roots or stem fragments. Flowers are white with four star-shaped petals, which sometimes have pink streaks in the center and two sepals. Fruit are green, elliptically shaped, hairy and ridged.

For info on managing this weed:

See entire publication

Or see sections of the publication on:

Identifying and Treating Winter Kill in Turf

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Clint Waltz, UGA Extension Turf Specialist

Image - Winter kill in centipede taken from presentation by Clint Waltz, UGA Turfgrass Specialist
Image – Winter kill in centipede taken from presentation by Clint Waltz, UGA Turfgrass Specialist

We’ve received many questions regarding grass that has failed to green-up this spring.  With variations among four different warm-season species, multiple climatic conditions, and because of the wet conditions leading to a likelihood of disease, there is much to be said on the topic of “winter kill”.   In many incidents there are circumstances and extenuating factors that make a specific diagnosis difficult. If there were a year for winter kill, after the cold conditions this past winter and early spring, this would be the year for it.

Click here for a brief presentation about Winter Kill.

Dr. James McCurdy at Mississippi State has written a good blog on winter kill in his state, and over the past 30 to 45 days I’ve seen many of the same issues in Georgia so my comments would be consistent with his.

  • In many cases, bermudagrass has greened-up and is beginning to grow.  I’ve seen a few lawns and pictures of some bermudagrass that is still brown.  Patience may be the key with bermudagrass.  Soil temperatures have only been conducive for growth for about two weeks.  Remember bermudagrass has rhizomes, below ground stems, that were likely well insulated by soil.  Warmer temperatures and time will likely be suitable for bermudagrass recovery.  Check for extenuating factors like shade and ask questions about how long ice or snow remained on the lawn / grass.  I have seen some incidences where sledding occurred and the brown tracks are consistent with the path of wintertime fun.
  • Hybrid bermudagrass have recovered better than common-type (i.e. seeded) bermudagrasses.  The commons are recovering – all be it slowly.
  • Zoysiagrass have fared well but are slow to resume active growth.  See my comments for bermudagrass regarding soil temperatures and patience.  Remember, zoysiagrass is inherently a slow growing species, so recovery is going to take time.  It too has rhizomes and with time will regenerate itself as environmental conditions become favorable for growth.  To help, vertical mowing (i.e. verticutting) can aid in getting light and warmth to the soil surface.  This cultural practice can help remove dead leaf material and speed recovery.
  • Centipedegrass and St. Augustinegrass have suffered the greatest.  There are many cases where reestablishment is going to the best option.  Consider making the decision early (i.e. now) and getting started with sodding or seeding as soon as possible (see slides)
  • Grass that was sodded last year is a hit or miss. Some bermudagrass and zoysiagrass that is less than a year old seems to greening-up and doing fine. Some is not. This is more likely a result of post establishment care, position within the landscape, and how late into the summer or fall the grass was sodded. Grasses planted earlier in the summer seem to be doing better than those established later. That stands to reason as the earlier planted grass had more time to establish and produce rhizomes and roots before the onset of winter. However, I’ve seen some zoysiagrass sodded earlier in the summer, on a northern exposure that didn’t make it through the winter. Water wasn’t an issue most of 2013, third wettest year on record. As a result, the associated lack of ample sunshine during the 2013 growing season may have contributed to suboptimal establishment and production of carbohydrates – a biochemical molecule responsible for energy and energy storage. With compromised production of carbohydrates, the turfgrass plant had less stored energy to initiate growth (i.e. green-up) this spring.
  • Fortunately I have not seen many incidences where I think early spring fertilization is the primary culprit for “winter kill”. But I have spoken with a few homeowners and landscapers that applied nitrogen in late February and early March, before soil temperatures were conducive for warm-season root growth (65ᵒ F). One was a centipedegrass lawn where the early fertilization coupled with the “Easter freeze” likely affected the majority of the lawn. From what I’ve observed to this point, I think the early fertilization is more closely linked to increased occurrence of disease (e.g. large patch) which is making homeowners think their lawn was affected by the low temperatures. Regardless of year, this issue is self-imposed and 100% avoidable.
  • In my plots the three primary St. Augustinegrass cultivars grown in Georgia (i.e. Mercedes, Palmetto, and Raleigh) have had some degree of damage.  The difficulty with St. Augustinegrass is that in sod production it typically does not “lift” well during the spring, do it’s early summer before producers can provide a quality product.  If a homeowner is considering re-sodding St. Augustinegrass, they can start site prep now but be prepared that quality sod may not be available until mid-June.
  • Typically I don’t consider environmental injury as a primary culprit to turfgrass loss, but after last summer and this past winter it’s real this year, especially for centipedegrass.  I’ve seen several centipedegrass, and St. Augustinegrass lawns, that will likely need complete re-grassing.  There is little that can be done to recover these lawns in a timely manner and “sanding” will likely be of little help.  TifBlair does have improved cold hardiness relative to common centipedegrass but this year I’ve seen it injured too but that seems specific to areas that remained under ice or snow for several days.  TifBlair in more open areas where the sun shortened the duration of snow cover seems to be delayed but greening.
  • If reestablishment either from sod or by seed is desired – now is an appropriate time for either practice.  In fact, if seeding is chosen – the earlier the better.  If the lawn was healthy going into the fall, seeding may be the better option.  The homeowner can mow the existing lawn low (i.e. scalp), collect the biomass (i.e. clippings), opening the canopy for seeds to make soil-to-seed contact.  By keeping some of the existing grass it may help speed recovery and provides a medium for seed to become established (i.e. a nurse grass).  The caveat to this is there was no preemergence herbicide applied this winter or spring.  If so, then don’t seed.  The herbicide will kill the germinating centipedegrass seed too.  Lastly, follow watering and establishment practices for a newly planted lawn.

State budget provides facilities enhancement, construction for UGA turf program

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Sharon Dowdy, News Editor with the UGA College of Agricultural and Environmental Sciences

For decades, University of Georgia scientists have conducted state-of-the-art turfgrass research. Today’s researchers still work in the same labs where modern turfgrass science started in the 1950s. Those legacy labs and greenhouses will soon get much-needed renovations.

Georgia’s FY015 budget includes $11.5 million for the improvement of the University of Georgia’s turfgrass teaching, research and Extension facilities across the state.

The funds will be used to build new greenhouses and research facilities on the UGA College of Agricultural and Environmental Sciences’ campuses in Athens, Griffin and Tifton.

Georgia’s turfgrass and related industries contribute more than $7.8 billion annually to the economy and provide 87,000 full- and part-time jobs. Turfgrass is one of Georgia’s top crops and provides 17 percent of the state’s farm gate value ($117 million).

“The urban ag industry has been a longtime supporter of Georgia’s turfgrass and horticulture education and research programs — and now Georgia’s legislators recognize the economic value that these industries bring to Georgia,” said Mary Kay Woodworth, executive director of the Georgia Urban Ag Council.

UGA Extension turfgrass specialist Clint Waltz credits the funding to the support of the council and UGA’s other green industry partners.

“World-renowned research and testing is accomplished at these UGA facilities and in the laboratories — and all are woefully outdated,” Woodworth said. “In order to continue to attract the best and brightest researchers and experts, we need state-of-the-art educational and research facilities. This funding will provide what we need to not only attract, but retain world-class turfgrass and horticulture experts.”

On the main UGA campus in Athens, the funding will be used to complete construction of an indoor and outdoor research laboratory that includes, a greenhouse, classrooms and new research field plots. Collectively, these new additions will become the college’s Athens Turfgrass Research and Education Center.

On the UGA Griffin Campus, the funds will go to construct a complex that includes a turfgrass research and education building, greenhouses and associated support offices and workspace.

“This project will continue the Griffin Campus’ tradition of cutting edge turfgrass research, attracting world class researchers and educators, graduate students, cooperators and industry. The UGA Turf Team is humbled by the industry’s support of our programs and appreciates all their efforts to garner funding for these facilities enhancements,” said Waltz who is based in Griffin.

The Tifton campus will see a new greenhouse complex.

“The necessity for new greenhouse facilities has become more critical during the past few years so that the level of research and development which has come to be expected from UGA’s Tifton Campus Turfgrass Breeding Program can continue,” said UGA turfgrass researcher Brian Schwartz who currently works in greenhouses built more than 50 years ago.

For more on turfgrass teaching, research and Extension programs at UGA, see the website www.GeorgiaTurf.com and follow on Twitter @GeorgiaTurf.

Controlling Annual Bluegrass and Lespedeza in Turf

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Helpful publications from Patrick McCullough, UGA Extension Weed Specialist

Annual Bluegrass Control in Residential Turfgrass

Annual bluegrass (Poa annua L.) is a problematic winter annual weed in residential turf. Compared to most turfgrasses, annual bluegrass has a lighter green color, coarser leaf texture and produces unsightly seedheads.

Contrary to its name, both annual (live for one season) and perennial (live for many seasons) biotypes of annual bluegrass may be found in turf.

This publication describes methods of control for annual bluegrass in residential turfgrass lawns.

To see the entire publication visit this site.

 

Annual Bluegrass Control in Non-Residential Commercial Turfgrass

 

Lespedeza Identification and Control in Turfgrass

Common lespedeza is a freely-branched summer annual legume that is a problematic weed in lawns and other turf areas. Common lespedeza, also known as Japanese clover or annual lespedeza, has three smooth, oblong leaflets with parallel veins that are nearly perpendicular to the midvein. As common lespedeza matures, the stems harden and become woody, which is attributed to persistence and competition with turfgrasses in late summer. Flowers are pink to purple and present in the leaf axils. Other lespedeza species may also be found as weeds in turf but common lespedeza is the primary species in Georgia.

Lespedeza McCullough
Lespedeza, Patrick McCullough, UGA

This publication describes ways to identify and control lespedeza in turfgrass, including:

To see the entire publication visit this site.

 

Here are other UGA turf weed control publications:

 

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