TURF TIPS

James A. McAfee, Ph.D.

Extension Turfgrass Specialist

Texas AgriLife Extension Service

Dallas, Texas

April 2, 2011

Spring Transition:

By now, most of the warm season turfgrasses have broken dormancy (greening up) and started to grow.  The bermudagrass lawns are further along than the St. Augustinegrass and the centipedegrass lawns in spring green up.  However, if no green up has occurred in the lawn or in sections of the lawn, then winter kill may be a problem.  So far, it appears that the degree of winter kill/winter injury is a lot less than what was anticipated following a very cold winter period.   Added to the low temperatures in the winter months are the extremely dry conditions across the state.  Most areas of the state have been dry since last fall and if homeowners did not apply some supplemental irrigation to their landscape during the fall and winter months, then this could have added to the problems associated with low temperatures injury.

Providing adequate supplemental irrigation for spring green up is very important.  If rainfall does not occur, then approximately 1.0 inch of supplemental irrigation water should be added to the lawn each week.  While it is important to make sure adequate soil moisture is available for spring transition, it is also important to make sure the landscape is not over watered.  Excess irrigation will create shallow rooted plants going into the hot, dry summer months and it can also encourage disease problems such as gray leaf spot in St. Augustinegrass.  Also, with the dry conditions we need to make sure irrigation is being applied to the landscapes as efficiently as possible so there will be adequate water for the rest of the year.

Factors to help turfgrass through spring transition:

  1.  Provide adequate soil moisture for good spring growth.  Again, approximately 1.0 inch per week if

        adequate rainfall does not occur should meet the needs of the turfgrass plants.

  2.  While it is too late to scalp the turfgrass growing in the lawn, mowing the grass slightly lower than

        normal and mowing it at least once per week will help force the grass to spread laterally and form a

       dense stand of turfgrass.  As temperatures start to warm up, mowing the turfgrass more than once per

       week will help to force the grass to spread faster and form a dense lawn.  Low, frequent mowing

       along with fertilizer is the best way to force thin areas in the lawn to grow and thicken up in the

       spring months.

3.  During the spring transition, use herbicides carefully, especially on the St. Augustinegrass and

      Centipedegrass lawns.  While bermudagrass and zoysiagrass can tolerate the spring applications

      of most herbicides, St. Augustinegarss and Centipedegrass can be injured in some years.  This is

      especially true for lawns that might have already been injured by the hard freezes last winter.  Once

      the grass has totally greened up and is actively growing, then it should be safe to make a postemergent

      herbicide application to the lawn.

4.  Monitor the lawn for any insect or disease problems.  If a pest problem occurs, then apply appropriate

      controls to prevent the disease or insect from causing any damage.  Fortunately, there are not a large

      number of insect and disease problems at this time of the year on the warm season turfgrasses.

Weed Control:

By now most people are aware that after December 31, 2010 organic arsenical herbicides such as MSMA, DSMA, etc. cannot be sold for use in residential lawns, commercial lawns, sports fields and right-of ways.  However, if you purchased one of the organic arsenical herbicides prior to this deadline and still have some in inventory, then it can be used until you have depleted the inventory.  The organic arsenicals herbicides can still be purchased for use on golf courses, sod farms and on cotton farms.  For lawns and sports fields, the one weed that is going to be difficult to selectively control in bermudagrass and zoysiagrass is dallisgrass.  At this stage, there really isn’t an effective herbicide for the selective control of dallisgrass.

With the losss of the organic arsenicals such as MSMA, it is going to be even more important that a spring preemergent herbicide application be applied for the control of summer annual grassy weeds such as crabgrass.  In past, some people would use MSMA as a postemergent control for grassy weeds in large turf areas such as sports fields, golf fairways, etc.  Cost of using the MSMA was generally less expensive than applying a preemergent herbicide.  Now with the loss of MSMA, using a preemergent in the spring is going to probably be the best control for summer annual grassy weeds.  Note, I still do not recommend a preemergent herbicide in spring for St. Augustinegrass and Centipedegrass lawns.

The herbicide Drive XLR 8 (quinclorac) does work pretty good as a postemergent on some grassy weeds such as crabgrass, barnyardgrass, broadleaf signalgrass and torpedograss.  It is also affective on some of the broadleaf weeds commonly found in lawns.  For the warm season turfgrasses, quinclorac is only labeled for use in bermudagrass, buffalograss and zoysiagrass.  It can also be used in cool season turfgrasses such as Kentucky bluegrass, Tall Fescue and Perennial ryegrass. There are also several new herbicides on the market that contain quinclorac plus some of the hormone type herbicides which provide not only grassy weed control, but a wider range of broadleaf weeds. Also, there are several new products found in the garden/retail stores that contain quinclorac.

While the quinclorac will do a pretty good job of controlling crabgrass, timing is going to be very important.  Quinclorac does a good job on young crabgrass seedlings and also works well on mature crabgrass plants.  However, it is not as nearly effective for the intermediate stages of crabgrass growth.

New Herbicides:

Listed below are some of the new commercial brand herbicides sold for weed control in different turfgrass sites.  Some of these new herbicides are also available in herbicides sold in the garden/retail stores.  I have included several herbicide tables that contain the more commonly sold herbicides for use in home lawns.

  1.  Celsius (thiencarbazone, iodosulfuron, dicamba)

      a.  sold by Bayer Environmental Services

      b.  at this time not available in garden/retail stores

      c.  can be used in bermudagrass, St. Augustinegrass, Centipedegrass, zoysiagrass and buffalograss.

      d.  can be used to control broadleaf weeds in St. Augustinegrass and Centipedegrass lawns.  There

            are fewer and fewer herbicides labeled for broadleaf weed control in these lawns.

      e.  while it is primarily a postemergent broadleaf herbicide, some university researchers have observed

           good control of young crabgrass seedlings.  However, Bayer wants to see more research before

           they place crabgrass on the label.

2.  Specticle ( indaziflan)

      a.  also new product from Bayer Environmental Services

      b.  sold as a preemergent herbicide for use on bermudagrass, St. Augustinegrass, Buffalograss,

            Centipedegrass, Bahiagrass and Zoysiagrass.

      c.  Applied at extremely low rates, 2.5 to 5.0 ounces per acre.

      d.  Excellent control of crabgrass, goosegrass and poa annua.

      e.  At this time is not available in the garden/retail market.

3.  Lockup ( penoxsulam )

      a.  manufactured by Dow AgroSciences.

      b.  Dow is selling the active ingredient to different companies so they can make their own

           formulations.  Note, the Lockup is sold primarily as a granular product at this time. 

      c.  Some companies are adding other postemergent herbicides such as 2,4-D and Dicamba to

           help increase activity of the penoxsulam. 

      d.  Lockup is being sold as herbicide only or some companies are blending it with a fertilizer and

           selling it as a weed and feed.

      e.  Lockup is labeled for use on bermudagrass, Centipedegrass, zoysiagrass, Kentucky bluegrass,

           perennial ryegrass and some fescues.

      f.  Has shown good activity on dollar weed, English daisy and white clover, but will also control

           other broadleaf weeds.

4.  Katana (flazasulfuron )

      a.  sold by PBI/Gordon, Inc. in the US

      b.  newest sulfonylurea herbicide

      c.  can be used in bermudagrass, centipedegrass and zoysiagrass.

      d.  excellent control of tallfescue

      e.  good ryegrass transition herbicide, works faster and in cooler weather than other sulfonylurea

           herbicides.

      f.  works well on most of the sedges as well as some broadleaf weeds.

5.  Solitare ( sulfentrazone + quinclorac )

      a.  manufactured by FMC

      b.  can be used on tall fescue, perennial ryegrass, bermudagrass, buffalograss, centipedegrass and

            zoysiagrass.

      c.  good activity on numerous broadleaf weeds and some of the sedges.

  6.  One Time ( quinclorac, mecroprop, dicamba )

      a.  manufactured by BASF

      b.  can be used safely on Kentucky bluegrass, buffalograss, tall fescue, ryegrass and zoysiagrass.

      c.  controls some of the grassy weeds such as crabgrass, foxtail and barnyard grass plus numerous

           broadleaf weeds.

Following are several tables containing different herbicides sold in the garden/retail stores for purchase by homeowners.  These are not complete lists of herbicides found in the garden/retail stores, but do contain some of the more commonly found products.  Also, different stores carry different herbicide brands, so you may have to look at more than one store to found all of these herbicides.

It is always important to emphasize the importance of reading these herbicide labels before purchasing the herbicide and before applying the herbicide.  These labels change and it is important to make sure it is still labeled for the type of turfgrass being grown in the lawn and that it is labeled for the weed that you are trying to control.

Table 1.  Postemergent Herbicides for Control of Grassy Weeds in Home Lawns.

Common Name                                Trade Names (partial list)

1.  2,4-D, Quinclorac,                         Bayer Advanced Lawn Weed & Crabgrass Killer

       Dicamba                                       Ferti-lome Weed Out With Q

2.  Quinclorac, mecroprop_p,             Ortho Weed B Gon Max Plus Crabgrass Killer

        2,4-D, Dicamba

3.  sulfentrazone, quinclorac              Image Kills Crabrass

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Remember, the herbicide quinclorac is only labeled for use in bermudagrass and zoysiagrass, so none of these products can be used in a St. Augustinegrass or Centipedegrass lawn.

Table 2.  Postemergent Herbicides for Control of Broadleaf Weeds in Home Lawns.

Common Name                                Trade Names (partial list)

1.   2,4-D                                          2,4-D Amine No. 4; 

                                                         American 2,4-D Selective Weed Killer

                                                        

2.   2,4-D, MCPP, dicamba              Ace Spot Weed Killer

                                                         Green Light Wipe Out Broadleaf Weed Killer2

                                                         Ortho Weed-B-Gon Max

                                                         Specracide Weed Stop for Lawns

                                                         Hi-Yield Lawn Weed Killer

                                                         Ferti-lome Weed-Out Lawn Weed Killer

3.   carfentrazone, 2,4-D,                 Ferti-lome Weed Free Zone

      Mecroprop_p, dicamba              Weed B Gon Max for Southern Lawns

4.  2,4-D, mecroprop_p,                 Bayer Advanced Southern Weed Killer for Lawns   

       dicamba                                   Spectracide Weed Stop for Lawns

                                                        Ferti-lome Weed Out lawn Killer

         

5.   2,4-D, mecroprop,                    Total Lawn Weed Killer

          dichloprop  

6.   2,4-D, mcpp, dicamba,             Spectracide Weed Stop 2X for Lawns

         sulfentrazone

7.   mecroprop_p, 2,4-D,                Weed B Gon for Southern Grasses

      dicamba

                                                       

8.   2,4-D, triclopyr, dicamba         Weed B Gon Max Kills Weeds, Not Lawns

9.   2,4-D, Quinclorac, dicamba      Bayer Advanced Lawn Weed & Crabgrass Killer

                                                          Ferti-lome Weed Out With Q

                                                          Ortho Weed B Gon Max plus Crabgrass Control

10.  penoxsalum                               Green Light Wipe Out Tough Weed Killer for Lawns

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Table 3.  Herbicides for control of Sedges in Home Lawns.

Common Name                           Trade Names (partial list)

1.  imazaquin                                Image Kills Nutsedge 

2.  halosulfuron-methyl                Gowen Sedgehammer 

3.  sulfentrazone +                        Image Kills Crabgrass 

        quinclorac                                                                                                                                                    

Table 4.  Preemergent Herbicides for Use in Home Lawns.

Common Name                           Trade Names (partial list)

1. dithiopyr                                Greenlight   Crabgrass Preventor2

                                                   Hi-Yield Turf & Ornamental With Dimension

                                                   Vigoro Weed Stop Crabgrass and Weed Preventor

2. pendimethalin                        Scotts Halts Crabgrass Preventor,

                                                   Lesco Crabgrass Pre Plus Potash (0-0-7)

3. oryzalin                                  Southern Ag. Surflan A.S.

4. isoxaben                                 Portrait Broadleaf Weed Preventor

5. benefin + oryzalin                  Green Light Amaze Grass & Weed Preventor

6. benefin + trifluralin               Hi-Yield Crabgrass Control with Balan

                                                   Southern Ag. Team 2 G

7. corn gluten meal                    Concern All Natural Weed Preventor Plus

                                                   Nature’s Guide Corn Gluten Meal

Spring Cultural Practices:

  1.  Fertilization:  In the spring, wait until the turfgrass is green and actively growing     before applying the

        first application of fertilizer.  Apply approximately 1.0 lb. of actual nitrogen per 1,000 sq.ft.. 

       Ideally, amount of phosphorus and potassium applied along with the nitrogen should be determined

        by soil test results ( fertilizer ratio).  Many of our soils in Texas are high to very high in phosphorus

        and potassium and in these cases all you need to apply is straight nitrogen.  If a soil test has not been

       conducted, then recommend  a 4-1-2 to 3-1-2 fertilizer ratio.  Not all soils are high in phosphorus and

        potassium and if you are applying only nitrogen, then the turfgrass will become stressed.

       In heavily shaded areas, apply 0.5 lbs. of total nitrogen per 1,000 sq.ft., unless this is the only

       application that is going to be applied to the heavily shaded portions of the lawn.  Excess nitrogen

       in shade will eventually cause major problems with the turfgrass growing in these areas.

      Depending on type of turfgrass, soil type, environmental conditions (sun vs. shade) and level of

      maintenance desired, make a second application in approximately 5 to 6 weeks after the spring

      application.

2.  Mowing:  As previously mentioned, mowing the lawn at a lower height and more frequently will

      force the turfgrass to spread faster and form a denser stand of turfgrass.  The key is to mow the

      turfgrass often enough so that you never remove more than 30 to 40% of the leaf blade when the

      grass is mowed.  Removal of excess leaf tissue inhibits the plants ability to carry on photosynthesis

      properly, which means that the plant cannot produce enough food for new growth, especially new leaf

      growth. 

      Mowing frequency is going to be determined by height of cut and growth rate.  The lower the grass is

      mowed, the more frequently it needs to be mowed.  The more the grass is fertilized and watered, the

      more often it will need to be mowed. Mowing at the proper height and frequency will produce a

      denser stand of turfgrass, a deeper root system and more stored carbohydrates in the plant.

     Listed below are the recommended mowing heights and frequency for turfgrasses growing in home

     Lawns.  Note, frequency will vary during the year due to day length differences and due to changes

     in temperature.  In fall and spring, when we have longer nights and cooler nighttime temperatures, the

     warm season grasses are not going to be growing as fast as they will in late spring through early fall

     months.

     Recommended mowing height and frequency for turfgrasses growing in home lawns.

     Turfgrass                              mowing height                                            mowing frequency

                                                          (inches)                                                            (days)

Common bermudagrass                 1.5 to 2.5                                                             3 to 4

Hybrid bermudagrass                    0.75 to 1.5                                                            2 to 3

St. Augustinegrass (sun)                 2.0 to 3.0                                                            3 to 5

St. Augustinegrass (shade)             3.0 to 4.0                                                             6 to 7

Centipedegrass                                1.5 to 2.0                                                            4 to 5

Zoysiagrass (japonica)                    1.0 to 2.0                                                            4 to 5

Zoysiagrass (matrella)                    0.5 to 1.5                                                            3 to 4

Buffalogrss                                      2.5 to 4.0                                                           5 to7

3.  Irrigation:  As previously mentioned, it is very important to provide adequate moisture for good spring

     transition of the warm season turfgrasses.  Applying approximately one inch per week if adequate

     rainfall does not occur should meet the plants needs.  As temperatures start to heat up, then it maybe

     necessary to increase the rate of water applied each week.  Ideally, the rate of water applied to the

     landscape should be based on the PET (potential evapotranspiration ) rate for the week.  Note, if you

    are not familiar with the ITC-TexasET Network, this is a excellent site for finding ET rates for different

      parts of the state.  The web address for this site is:  http://texaset.tamu.edu/

 

Fireblight Study Looks At New Chemical, Biological and Biorational Controls

OVERTON -- A Texas AgriLife Extension Service plant pathologist has begun evaluating new products, both chemical and biological, to control fireblight on peach and apple trees.

"Fireblight is a really big issue for commercial fruit producers of pears and apples, but also for homeowners and nursery growers who produce trees for homeowners," said Dr. Karl Steddom, plant pathologist.

Steddom is conducting the study at the Texas AgriLife Research and Extension Center at Overton where he is based.

Fireblight is the most devastating bacterial plant disease affecting apple and pear trees, according to Steddom.

The bacterium is usually introduced into the plant in the early spring as bees and other insects pollinate newly blooming flowers, he said.

Once introduced, the disease progresses very rapidly. The flowers soon start to rot and turn black, looking as if they've been burned by a torch.

"Hence the name fireblight," Steddom explained.

Within a week or two, the bacteria work their way down the flower stem into the new shoot via the tree's vascular system.

"As it works its way down, you'll start to lose leaves, and the whole shoot will die down to where it started its growth this year," he said.

Currently, there are only three products registered for use for fireblight on fruit trees.

"And we don't know (lacking independent tests), how well two of those products really work," Steddom said.

The tried-and-proven method, copper fungicide, involves spraying "pretty much every week" throughout the spring growing season, he said. The process is expensive and labor intensive for commercial growers, and more work than homeowners usually want or have time to do.

The treatment also leaves a bluish residue on plants that homeowners often object to, Steddom noted.

Copper fungicide isn't a restricted-use pesticide, which means homeowners won't need to have a Texas Department of Agriculture license to buy or use it, he said. However, it's not usually available in home and garden stores.

"And the trees don't end up looking that good, even with all that work," Steddom said. "So what we're doing is testing a number of old and new products to see how they perform."

For the test, Steddom inoculated 144 Kieffer trees with the fireblight bacterium. For the test, the container-grown trees were spaced 5 feet apart in a single row about 750 feet long.  The single row allows him to control spray drift better from tree to tree than if he used a standard orchard arrangement,
he explained. This is important in order to limit a given spray treatment to a single tree.

Steddom is testing a total of 13 products, including copper fungicide and the other two registered chemical controls, plus ten products that are not yet commercially available. Some of the products are chemical controls; some biologicals. He is also comparing a relatively new class of pesticides called "biorationals," which, strictly speaking, are not biological, but are derived from biologicals.

"The biorationals are supposed to be effective and more environmentally friendly than chemicals, but we'll see," he said.

Currently, Steddom and AgriLife Extension don't recommend a frequent spray schedule for homeowners. Instead, the recommendation is to let the disease progress into the summer when days are warmer and drier.

"You want to wait until it's warmed up quite a bit, otherwise when you cut the shoot, the bacterial will get on your shears, and you'll transfer that bacteria from place to place," he said.

Shears may be sanitized after pruning one shoot before the next, but it generally takes a couple of minutes submerged in rubbing alcohol to kill the fireblight bacteria, according to Steddom.  

Bleach can also be used, but it tends to cause shears to quickly rust.

"So an alternative is to use two pairs of shears," he said. "While you're trimming one shoot with one pair, the other pair can be sitting in the alcohol, disinfecting."

The one-year study was funded by the U.S. Department of Agriculture’s IR-4 Project, which is also referred to as the Minor Crop Pest Management Program.  The full results will be available sometime in the fall of this year on the IR-4 website at http://ir4.rutgers.edu/ .

If some products show substantial or even partial control, IR-4 may fund the study a second year, Steddom added.

"It all depends upon what we learn this first year," he said.

Until the results of the study are known, growers or homeowners wanting more information about fireblight control in home orchards should contact their local county AgriLife Extension agent, he said.

A county-by-county directory of AgriLife Extension agents can be found at http://county-tx.tamu.edu/ .