Landscape Alert – September 2017

Fall Turfgrass Disease Prevention and Control  

by Alfredo Martinez

Large Patch

Rhizoctonia large patch is the most common and severe disease of warm season grasses (bermudagrass, centipedegrass, seashore paspalum, St. Augustinegrass, and zoysiagrass) across the state of Georgia. Due to spring and fall disease-promoting environmental conditions across Georgia coinciding with grasses leaving and/or entering dormancy, large patch can appear in warm season grasses in various grass-growing settings, including home lawns, landscapes, sports fields, golf courses, and sod farms. Symptoms of this lawn disease include irregularly-shaped weak or dead patches that are from 2 feet to up to 10 feet in diameter. Inside the patch, you can easily see brown sunken areas. On the edge of the patch, a bright yellow to orange halo is frequently associated with recently affected leaves and crowns. The fungus attacks the leaf sheaths near the thatch layer of the turfgrass.

photo of turfgrass disease large patch

Large patch disease is favored by:

  • Thick thatch.
  • Excess soil moisture and poor drainage.
  • Too much shade, which stresses turfgrass and increases moisture on turfgrass leaves and soil.
  • Early spring and late fall Nitrogen fertilization.

If large patch was diagnosed earlier, fall is the time to control it. There is a myriad of fungicides that can help to control the disease. Fungicides in the following classes are labeled for large patch control: carboxamides, benzimidazoles, carbamates, dicarboximides, DMI fungicides, di-nitro anilines, control. For a complete and updated list of fungicides available for commercial control of large patch, visit http://extension.uga.edu/publications/detail.cfm?number=SB28  or http://www.commodities.caes.uga.edu/turfgrass/georgiaturf/Publicat/1640_ Recommendations.html.  Preventative or curatives (depending on the particular situation) rates of fungicides in late September or early October and repeating the application 28 days later are effective for control of large patch during fall. Fall applications may make treating in the spring unnecessary. Always follow label instructions, recommendations, restrictions and proper handling.

Cultural practices are very important in control. Without improving cultural practices, you may not achieve long term control.

  • Use low to moderate amounts of nitrogen, moderate amounts of phosphorous and moderate to high amounts of potash. Avoid applying nitrogen when the disease is active.
  • Avoid applying N fertilizer before May in Georgia. Early nitrogen applications (March-April) can encourage large patch.
  • Water timely and deeply (after midnight and before 10 AM). Avoid frequent light irrigation. Allow time during the day for the turf to dry before watering again.
  • Prune, thin or remove shrub and tree barriers that contribute to shade and poor air circulation. These can contribute to disease.
  • Reduce thatch if it is more than 1 inch thick.
  • Increase the height of cut. Reduced mowing heights result in a more dense turf stand, which may create a more favorable environment for large patch development
  • Improve the soil drainage of the turf.
  • Control traffic patterns to prevent severe compaction, and core aerate to improve soil drainage and increase air circulation around the shoots and root

For more information on large patch visit https://secure.caes.uga.edu/extension/publications/files/pdf/C%201088_2.PDF

  

Spring Dead Spot of Bermudagrass

Fall cultural practices and fungicide applications are key for Spring Dead Spot management. The disease is caused by fungi in the genus Ophiosphaerella (O. korrae, O. herpotricha and O. narmari). These fungi infect roots in the fall predisposing the turf to winter kill.  As indicated by its name, initial symptoms of spring dead spot are noticeable in the spring, when turf resumes growth from its normal winter dormancy.  As the turf ‘greens-up,’ circular patches of turf appear to remain dormant, roots, rhizomes and stolons are sparse and dark-colored (necrotic).  No growth is observed within the patches.  Recovery from the disease is very slow. The turf in affected patches is often dead; therefore, recovery occurs by spread of stolons inward into the patch.  The causal agents of SDS are most active during cool and moist conditions in autumn and spring. Appearance of symptoms is correlated to freezing temperatures and periods of pathogen activity. Additionally, grass mortality can occur quickly after entering dormancy or may increase gradually during the course of the winter. Spring dead spot is typically more damaging on intensively managed turfgrass swards (such as bermudagrass greens) compared to low maintenance areas.

photo of turfgrass disease spring dead spot

  • Practices that increase the cold hardiness of bermudagrass generally reduce the incidence of spring dead spot. Severity of the disease is increased by late-season applications of nitrogen during the previous fall.
  • Management strategies that increase bermudagrass cold tolerance such as applications of potassium in the fall prior to dormancy are thought to aid in the management of the disease. However, researchers have found that fall applications of potassium at high rates actually increased spring dead spot incidence. Therefore, application of excessive amounts of potassium or other nutrients, beyond what is required for optimal bermudagrass growth, is not recommended.
  • Excessive thatch favors the development of the disease. Therefore, thatch management is important for disease control,
  •  Implement regular dethatching and aerification activities.
  • There are several fungicide labeled for spring dead spot control.
  • Timing, selection and application of fungicides are important for preventative management of SDS. Fungicide application in the fall when soil temperatures are between 60° and 80° F provides the best control of SDS
  • A complete list of fungicides, formulations and product updates for SDS can be found in the annual Georgia Pest Management Handbook and the Turfgrass Pest Control Recommendations for Professionals (http://www.georgiaturf.com). Some fungicide options are exclusively for golf course settings. Always check fungicide labels for specific instructions, restrictions, special rates, recommendations, follow-up applications and proper handling.

For more information on SDS visit https://secure.caes.uga.edu/extension/publications/files/pdf/C%201012_3.PDF

 

Early detection of bermudagrass leaf spot 

Severe leaf and crown rot, caused by Bipolaris ssp. can occur in bermudagrass lawns, sport fields, or golf fairways. Initial symptoms of this disease include brown to tan lesions on leaves.  The lesions usually develop in late September or early October.  Older leaves are most seriously affected.  Under wet, overcast conditions, the fungus will begin to attack leaf sheaths, stolons and roots resulting in a dramatic loss of turf.  Shade, poor drainage, reduced air circulation; high nitrogen fertility and low potassium levels favor the disease. To achieve acceptable control of leaf and crown rot, early detection (during the leaf spot stage) is a crucial.

Photo of turfgrass disease Bermudagrass Leaf SpotPhoto 2 of turfgrass disease Bermudagrass Leaf Spot

Dollar spot is still active in the fall/early winter

Dollar spot is most prevalent during spring and fall with infections developing rapidly at temperatures between 60 and 75 degrees Fahrenheit combined with long periods of leaf wetness from dew, rain, or irrigation.

  • Excessive moisture on turfgrass foliage will promote dollar spot epidemics. Irrigating in the late afternoon or evening should be avoided, as this prolongs periods of leaf wetness.
  • If feasible, prune or remove trees and shrubs to promote air movement and accelerate drying of the turfgrass canopy
  • A variety of fungicides are available to professional turfgrass managers for dollar spot control including fungicides containing benzimidazoles, demethylation inhibitors
    (DMI), carboximides, dicarboximides, dithiocarbamates, nitriles and dinitro-aniline. Several biological fungicides are now labeled for dollar spot control.
  • For a complete and updated list of fungicides available for dollar spot, visit http://extension.uga.edu/publications/detail.cfm?number=SB28 or http://www.commodities.caes.uga.edu/turfgrass/georgiaturf/Publicat/1640_Recommendations.htm.

photo: turfgrass disease dollar spot photo: turfgrass disease dollar spot2

Additional information on dollar spot visit https://secure.caes.uga.edu/extension/publications/files/pdf/C%201091_2.PDF

Warm-Season Vegetable Planting Chores for Georgia

Warm-season vegetable planting time is almost here for most of Georgia.  Here is your “to-do” list from UGA’s Vegetable Garden Calendar for this time of year:

Warm-Season Vegetable Planting Chores for Georgia
Belvedere Community Garden
  • Get rows ready for “warm-season” vegetables to be planted during the last week of March or first week or two of April as weather permits.  Check your soil temperatures at georgiaweather.net.
  • You might want to risk planting out a few of the more tender crops and keeping them covered during bad weather.
  • Watch out for insects, especially cutworms, plant lice (aphids) and red spider mites.
  • Put down mulch between rows to control weeds.
  • Plant your choices of the following “warm-season” or “frost-tender” crops: beans (snap, pole and lima), cantaloupe, corn (sweet), cucumbers, eggplant, okra, field peas, peppers, squash, tomatoes and watermelon.
  • Plant tall-growing crops such as okra, pole beans and corn on the north side of other vegetables to avoid shading. Plant two or more rows of corn for better pollination.
  • Make a second planting within two to three weeks of the first planting of snap beans, corn and squash.
  • Within three to four weeks of the first planting, plant more lima beans and corn. Remember: for better pollination, plant at least two or more rows.
  • Be sure to plant enough vegetables for canning and freezing.
  • Cultivate to control weeds and grass, to break crusty soil and to provide aeration.
  • For the crops planted earlier, side-dress as described above.
  • Plant tender herbs.
  • Remember: Do not work in your garden when the foliage is wet to avoid spreading diseases from one plant to another.

Contact your local UGA Extension office if you need any help choosing varieties!

Happy Gardening!

 

Aerification: Restoring Turfgrass Carbohydrate Reserves

Dr. Clint Waltz, Extension Turfgrass Specialist with the University of Georgia, reports that hot temperatures and low rainfall in the fall of 2016 likely sent warm-season turfgrasses into winter dormancy with depleted carbohydrate reserves. During “normal” circumstances warm-season turfgrasses accumulate and store carbohydrates from late summer through early fall.  Last year, non-irrigated turfgrasses likely suffered drought-induced dormancy and transitioned to winter a weakened condition.  With insufficient energy accumulated in root systems, a thin canopy and a two- to four-week delay in the green-up of warm-season grasses might be common this spring.

 

 

 

 

 

 

What can be done to improve the green-up and growth of warm-season turfgrasses this spring?

1) AERIFICATION – Core aerification in late April to mid-May.  This will improve air exchange and water infiltration to stimulate root and shoot growth.  Performing hollow-tine aerification that removes 1/2 inch diameter soil cores to a 3 or 4 inch depth is the recommended approach.

2) TIMING OF FERTILIZER – Withhold the application of nitrogen fertilizer until soil temperatures at the 4-inch depth are consistently 65 degrees and rising.  Visit www.Georgiaturf.com to find lawn calendars that include fertility recommendations for each species.  Soil temperature data from the Georgia Automated Environmental Monitoring System can be found at www.Georgiaweather.net.

3) SOIL TESTING – Collect a soil sample and submit for testing to ensure that soil Ph, phosphorous, and potassium levels are within the recommended ranges for optimum growth.  Contact your local UGA Extension Agent about submitting a soils sample to the UGA Agriculture and Environmental Services Laboratory or call 1-800-ASK-UGA1.

Restoring carbohydrate reserves this spring is an important step in preparing turfgrasses for a healthy growing season.  Read the full article by Dr. Clint Waltz at www.Georgiaturf.com.

Weed Scouting in Mid-Winter

Weeds can be a major pest of lawns and recreation fields, competing for resources and sunlight while detracting from their natural beauty.

If your spring checklist includes lawn weed management, now is the time to take a closer look at the tiny mat of weed seedlings forming in mid-winter (Jan-Feb.), especially during spells of mild weather and precipitation. The winter-weed inventory is likely to include a mix of early-stage cool-season annual and perennial weeds such as chickweed, henbit, clover, annual bluegrass, burweed, and wild garlic. One advantage of mid-winter weed scouting and management is that many weeds are in the early growth stages and can be effectively controlled by herbicide treatments. In addition, warm-season turfgrasses such as bermudagrass and zoysiagrass are dormant and less susceptible to herbicide injury than during spring green up. Mid-winter is an excellent time to scout for cool-season weed species and get an early jump on management while conditions are favorable.

Below are examples of lawn weeds commonly observed in mid-winter:

Pictured above: Henbit (left), Plantain (center), Tall Fescue in bermuda (right).

POSTEMERGENCE WEED CONTROL

Selective control of broadleaf and grassy weeds in turfgrass can be an effective strategy in mid-winter using the appropriate postemergence herbicide product(s). It should be noted that during the winter months the visible effects of certain herbicides may be masked by cool weather (the weeds may be dead and not know it yet!) Mature perennial weeds such as dandelion, clover, and undesired patches of tall fescue can be effectively spot-treated during mid-winter using selective and non-selective herbicides. It is essential to select products appropriate for the particular species or turfgrass when selecting herbicides. St. Augustinegrass and Centipedegrass are particularly susceptible to certain herbicide injuries, even during the winter months. Combination products containing fertilizer and herbicides may be appropriate for weed control in cool-season turfgrass species such as Tall Fescue during the late winter. However, combination products containing nitrogen fertilizer are NOT recommended for warm-season grasses during the winter months. Applying nitrogen to dormant warm-season grasses in mid-winter does not provide benefits to the turfgrass and promotes the development of diseases such as large patch.

Remember, turfgrass and weed identification is essential to determining the appropriate herbicide product, timing, and application rate. There are no miracle products or “one size fits all” solutions to weed control. Herbicide recommendations are based on many factors including the turfgrass species, weed species, temperature range, and environmental factors. For assistance with turfgrass and weed identification, contact your local UGA Extension Agent at 1-800-ASK-UGA1.

Download the 2017 Turfgrass Pest Control Recommendations for Professionals at www.GeorgiaTurf.com for the latest information on weed management, scheduling, and pesticide information.

References:

McCullough, Patrick E. PhD, Waltz, Clint PhD, (2015). UGA Extension Bulletin (C 978). “Weed Control in Home Lawns.”

Drought Response Level 2: Outdoor Watering Information

Prolonged dry weather has prompted an elevated drought response for northwest Georgia. Effective November 17, 2016, fifty-two counties have entered a drought response level 2 and fifty-eight counties are exercising a drought response level 1.  Rainfall has been scarce since August and water conservation is the banner message.  The Georgia Water Stewardship Act of 2010 establishes certain outdoor watering protocols to conserve water during times of drought.  These rules apply to all properties served by state permitted water systems.

Highlights of Drought Response Level 1:
A drought response level 1 initiates a public information campaign to explain drought conditions and the need for water stewardship and conservation.  Normal outdoor watering should follow best management practices and is allowed between the hours of 4:30pm and 10am any day of the week.

Highlights of Drought Response Level 2:
For existing landscapes, a drought response level 2 initiates the odd/even watering schedule by address for sprinkler systems.  For even addresses (ending in zero, 2,4,6,8) watering is allowed as needed on Wednesdays and Saturdays between the hours of 4pm and 10am.  For odd addresses (ending in 1,3,5,7,9) watering is allowed as needed on Thursdays and Sundays between the hours of 4pm and 10am.  Sprinkler systems should always be properly maintained and adjusted.  Evapotranspiration is much lower during the fall and winter and minimal irrigation is needed to prevent winter desiccation using a rate of 1/2 inch precipitation per week or less during periods of dry weather.

New Landscapes:
Under all levels of drought response, a 30 day exemption period is allowed for the establishment of new landscapes. Once the establishment period has expired, drought response watering practices should be followed accordingly.

Other Allowable Exemptions:
Handwatering using a hose with an automatic shut-off nozzle
Food gardens
Hydroseeding
Drip irrigation or soaker hoses
Horticulture crops intended for sale, resale, or installation
Athletic fields, golf courses, and public recreation areas
Maintenance or calibration of an irrigation system
Water from private wells and bodies of water on property (not exceeding state withdrawal limits)
Water from an alternate source (grey water, rain water, air-conditioner condensate)
Commercial Pressure Washing

Summary:
Stay informed on the latest drought information for your area (see helpful resources and information below).  While natural precipitation is generally sufficient to prevent plant desiccation in established landscapes during fall and winter, extremely dry conditions may require supplemental watering to help mitigate plant damage. Follow responsible watering practices and properly manage irrigation systems to protect plant health while promoting a culture of water conservation in Georgia.  Register for training opportunities such as the upcoming “Irrigation Training for Landscape Professionals” at the EDGE Expo at the Gwinnett Infinite Energy Center on December 8, 2016.

For more information on proper watering practices and training opportunities, contact your local UGA Extension Agent or call 1-800-ASK-UGA1.

Helpful Resources and Information:
http://extension.uga.edu/publications/
www.GeorgiaTurf.com
www.GeorgiaWatersmart.com
https://epd.georgia.gov/water-conservation

 

Water Conservation and Drought Awareness: Information about the Georgia EPD Drought Level 1 Response

On September 9, 2016, a drought level 1 response was issued by GEPD for 53 counties in northwest and central Georgia. Georgia’s drought management plan, as outlined by the Georgia Water Stewardship Act of 2010, establishes a three-tiered approach to water resource conservation and monitoring.  The first tier of the system is called “Drought Level 1” and initiates a conservation and public awareness campaign by local water utilities in affected counties. Look for forthcoming information regarding the drought level 1 response from local water authorities in these counties to help citizens better understand drought, its impact on water supplies and the need for indoor and outdoor water conservation.  drought_level_1_9-15-2016

 

Outdoor watering: Is it okay to plant trees and irrigate turfgrass?  Yes, normal outdoor watering is allowed between the hours of 4pm and 10am and new landscapes can be watered any day, any time for 30 days in accordance with the Georgia Water Stewardship Act. However, proper plant care and responsible watering practices should always be followed.

Contact your local University of Georgia Extension Agent for scientific publications, bulletins, and fact sheets regarding plant care and irrigation practices. Key practices include mulching, proper plant selection, raising mower heights, and proper irrigation.  In addition, the Georgia Urban Ag Council and the Georgia Green Industry Association launched a website called Georgiawatersmart.com outlining best management practices for indoor and outdoor water conservation.

According to the 2012 Annual Report, the Metropolitan North Georgia Water Planning District estimates that the 15 County Metro Atlanta area reduced per capita water consumption by as much as 20% between 2000 to 2010 through local water stewardship and conservation efforts. Spread the word about water conservation and drought awareness and stay informed on the latest practices for managing drought stressed landscapes.  For more information about the level 1, 2, and 3 drought responses, visit the Water Conservation page of the Georgia Environmental Protection Division website.

Related Articles:

Tips for Managing Drought Stressed Turfgrass

Drought Level 1 Declared in Georgia

 

 

Fire Up with the Saw Safety Team

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Pesticide Waste Collection (Clean Day) Event

The Georgia Dept. of Agriculture will host a Pesticide Waste Collection (Clean Day) event on September 30, 2106 at the Cordele State Farmers Market in Crisp County from 9:00am to 3:00pm. The Georgia Department of Agriculture is excited to have the funding to support this excellent program as a benefit to all Georgia citizens and the environment. The collection day is open to all who would like to participate.  Due to collection limits, pre-registration is required and must be completed by September 26, 2016.  Additional information and registration forms can be found online at http://agr.georgia.gov/georgia-clean-day.aspx

Don’t leave pesticide waste sitting around in storage waiting for an accident or spill to happen, take advantage of this rare opportunity to dispose of pesticide waste safely and responsibly.

For more information, please contact:

Rick Hayes
Georgia Department of Agriculture
19 MLK Jr. Dr. Room 410
Atlanta, Ga. 30334
Office: 404-656-4958 Ext. 4113
E-Mail: ricky.hayes@agr.georgia.gov

Related Post:

Disposing of Excess Pesticides in a Safe Manner

They’re Back – Handling Japanese Beetles in Your Garden

They are indeed back.  You have probably already seen Japanese Beetles (Popillia japonica) in your landscape.   They enjoy munching the leaves of roses, maple trees, cherry trees, peaches and grapes.  They actually are a pest to over 300 plant species.  A single beetle doesn’t do much damage.  Unfortunately once a beetle finds a food source other beetles soon follow.  It is the groups of beetles that do real damage.

These beetles will eat the leaves and petals of plants in the rose family.
These beetles will eat the leaves and petals of plants in the rose family.

Japanese beetles first arrived in the United States around 1917.  As with many non-native species, in their home country of Japan they are not a major problem.  This pest causes damage in the adult beetle stage as well as the larval stage.  The larvae, or grubs, live in the soil and can do damage to plant roots.

We often get questions from gardeners about these pests and thought it might be helpful to share them with you:

Do you need to worry about this pest?   

The Japanese Beetle season lasts 4-6 weeks, so realize they won’t be around for very long.  They are not a major pest of vegetable gardens and generally eat the leave margins leaving a lacy-type leaf.  They sometimes also eat petals and can damage fruit.

Do the Beetle Traps Work?

Yes, the beetle traps do work by attracting beetles from all over your area and bringing them to your yard! The traps contain a pheromone, a sex attractant, that can attract beetles that may not have visited your garden on their own.

If you decide to use traps, do not put them in the middle of your garden as you would just be bringing in additional numbers of the pests.  Also, the traps will need to be emptied often.  The dead beetles give off an ammonia scent that will repel other beetles.

Wouldn’t it be nice if your neighbors put out traps to attract your beetles to their yards?

Is Their a Non-Chemical Control?

Most home or community gardeners can control Japanese Beetles by simply picking the insects off the plants and dropping them in a container of soapy water.   By regularly scouting for these insects and removing them, you will prevent any real damage.  This is a great job for kids.

What if I Decide I Need an Insecticide?

There are insecticides available to kill Japanese Beetles but realize that the chemicals don’t affect just those beetles but possibly beneficial insects as well.  Contact your local UGA Extension Agent for a specific chemical recommendation.  As with all pesticides you will want to follow the label directions to the letter.

Wishing you a Japanese Beetle free garden! 

Spring Bleeding: Maple, Birch, Elm, Grapevines

Following a late winter or early spring pruning of Maple, Birch, Elm, or Grapevines it is common to observe “bleeding” from the pruning wounds.  This phenomenon usually occurs just before and during leaf emergence in the spring, especially during years of abundant soil moisture.  The temporary bleeding is generally not detrimental to the health of the plant and primarily consists of a watery sap solution. The bleeding usually ceases once the leaves have fully emerged and water begins to evaporate through the leaf stomata, creating transpirational pull that overshadows the root pressure.

The upward flow of water is caused by osmotic pressure in the root system that begins with the imbalance of water molecules between the soil and the root system.  A high concentration of minerals and carbohydrates in the root system generally translates to a lower concentration of water molecules when compared to the surrounding soil. Water molecules enter the root cells to equalize distribution, causing root cells to become turgid and force water upwards in the vascular system.  (Incidentally, the reverse is true when too much fertilizer is applied and a higher concentration of minerals in the soil prevents the osmotic absorption of water into the root system.)

Occasionally, bleeding can be a nuisance where these plants drip on parked cars and pedestrian spaces.  In such cases, delay pruning of these species until late spring-early summer to help to reduce the issue.

If prolonged bleeding occurs and you observe any unusual signs or symptoms of pests or disease, report the information to your local extension agent for further assessment.