Problem Weeds of Turfgrasses Tim R. Murphy Crop and Soil Sciences The University of Georgia

Why control weeds? Reduce crop yields and quality Lower aesthetic appeal and property value Some are allergens or poisonous Disrupt native ecosystems Harbor insects and diseases Interfere with right-of-way safety and transmissions

Weed Management Strategy Identify weed, life cycle, habitat Institute Control Procedures –Preventive –Mechanical –Biological –Cultural –Chemical

Virginia buttonweed

Virginia buttonweed (Diodia virginiana) Warm-season perennial broadleaf Reproduction –creeping stems – creeping roots – above and below ground seed production

Virginia buttonweed Seed germination - optimum at 85 to 95 F. - no germination < 70 F. - optimum depth 1.0 to 1.5 inches Shoot emergence - root fragments 0.25 inch long can produce shoots from 8 inch soil depth

Virginia buttonweed - Control 2,4-D + 2,4-DPGood 2,4-D + dicambaGood 2,4-D+MCPP+dicambaGood Research at MSU show formulations high in 2,4-D concentration provide better control (ex. Trimec Classic, Escalade) Spray regrowth when noted (21 to 35 days)

Virginia buttonweed - Control Ronstar - seed only Princep - seed only Confront, Manor - fair control (variable) Monument, Katana – good control (variable) Glyphosate - the last resort!

Sedge Herbicides - Turfgrasses Basagran T/O - yellow, annual sedges Manage, SedgeHammer - yellow, purple, annual sedges Monument - yellow, purple, annual sedges Katana - yellow, purple, annual sedges MSMA/DSMA - yellow, purple, annual sedges Image - yellow, purple, annual sedges Certainty – yellow, purple, annual sedges Pennant - yellow, annual sedges

Green (perennial) kyllinga

Kyllinga spp. (Kyllinga spp.) Sedge family Annuals and perennials Reproduce by seed and rhizomes No tuber formation Thrive in wet soils Increasing in severity Lack of MSMA use??

Kyllinga spp. - Control Image Image + MSMA Manage, SedgeHammer Katana Monument Certainty MSMA/DSMA Repeat applications will be needed

Sedge control ratings. Herbicide Annual Sedge Purple Nutsedge Yellow Nutsedge Annual Kyllinga Green Kyllinga PennantGFGF-GP CertaintyGG-E G Basagran T/OGPGF-G ImageGF-GP-FGG SedgehammerGGGGF-G MSMA/DSMAGP-FFGG Image+MSMAGG-EGGG Monument??G-EGG

Violet spp. (perennial)

Violets spp. (Viola spp.) Annuals and perennials Shade or full sun Reproduce by seed (rhizomes) 2- and 3-way products - P to F 2 appl. Confront, 3 to 6 wks apart 2 appl. Chaser, Turflon II Amine. 4 wks apart Katana, Manor, Blade

Wild garlic

Wild Garlic/Onion (Allium vineale and canadense) Cool-season perennial,reproduces by seed, aerial bulbils and underground bulbs and bulblets 2,4-D and other phenoxy products, 2 appl. 6 wks apart, 2 to 3 years Image - apply after dormancy, mow 1 to 2 wks after application Manor, Blade

Doveweed

Doveweed (Murdannia nudiflora) Summer annual, reproduces by seed fleshy stems, root at nodes 3 appl. MSMA + 2,4-D 2 appl. MSMA + Sencor Atrazine, 2 applications, 3 weeks apart 2 appl. Trimec Southern (14 d intervals)

Doveweed Ineffective Herbicides - Basagran T/O - Confront - Vanquish - Manor, Blade

Spreading dayflower

Spreading Dayflower (Commelina diffusa) Summer annual Reproduces by seed and stem fragments MSMA + Sencor Basagran T/O, Prompt MSMA Turflon II Amine (2,4-D + triclopyr)

Annual blue-eyed grass

Annual Blueeyed-grass (Sisyrinchium spp.) Annuals and perennials, Member of Iris family Reproduce by seed Thrives in compacted soils, some species like moist soils TranXit Triazines in late fall 2 appl. MSMA + Sencor, 14 d interval

Chamberbitter, niruri, gripeweed

Chamberbitter - Phyllanthus niruri Euphorbiaceae (spurge family) niruri, gripeweed, leafflower summer annual, reproduces by seed alternate leaves, numerous leaflets inconspicuous flowers stalkless green, round fruit no milky juice

Longstalked Phyllanthus

Longstalked Phyllanthus (Phyllanthus tenellus) Euphorbiaceae (spurge family) summer annual, reproduces by seed alternate leaves, numerous leaflets inconspicuous flowers stalked green, round fruit no milky juice

Chamberbitter & Longstalked Phyllanthus Control atrazine, simazine, 2 appl., 3 wks apart Ronstar - Pre (no home lawns) Gallery - Pre MSMA, 2 to 3 appl., 7 days apart ??? 2,4-D+MCPP+dicamba ???? Manor, Blade????

Prostrate spurge - summer annual Postemergence: Manor, Blade, Sencor, Trimec, Monument Preemergence: Simazine, atrazine, Gallery

summer annual fireweed Postemergence : 2- and 3-way growth regulator herbicides, Manor, Blade. Preemergence products are not very effective or provide only short term control. American burnweed (fireweed)

Pennywort or dollarweed perennial Atrazine or simazine applied twice, 30 days apart. Prompt, Image, Manor, Blade. 2 or 3-way broadleaf mixtures applied 7 days apart are also effective in tolerant turfgrasses.

Dichondra, rhizomatous perennial Controlled by repeat applications of atrazine, 30 days apart. 2 and 3-way growth regulator herbicides. Confront is a little better than Trimec related compounds. *Monument

Lawn burweed (spurweed)

Lawn Burweed - Soliva pterosperma Compositae (aster family) spurweed, sandbur winter annual, reproduces by seed opposite leaves fruits with sharp spines

Lawn Burweed Control atrazine, simazine - Pre or Post Gallery - Pre, early fall 2,4-D+MCPP+dicamba, repeat applications may be necessary Manor, Blade Katana

Florida betony

Florida Betony - Stachys floridana Labitae (mint family) “Rattlesnake weed” perennial reproduces primarily by tubers opposite, serrated leaves occurs in turf and ornamentals

Florida Betony Control atrazine - F-G 2,4-D - G 2,4-D+MCPP+dicamba - G Roundup, Finale Manor, Blade

Annual bluegrass – Poa annua Winter annual, but perennial biotypes also found on bentgrass greens Germinates late summer-fall at soil temperatures around 70 F. Second germination flush in mid- to late-winter

Continuous annual bluegrass seed germination occurred from mid-Nov. through early January in Knoxville, TN. Callahan and McDonald, 1992

Annual bluegrass control Preemergence Control Barricade, Pendulum Surflan, Dimension Balan, Ronstar Kerb Atrazine, Simazine annual bluegrass Boat shaped leaf tip

Non-Overseeded Bermudagrass Triazines – standard, but resistance increasing –Kerb – works, costly, lateral run-off –Pre’s – work, but DNA resistance is here –Glyphosate – works, partial dormancy –Diquat – ineffective Revolver, TranXit, Monument, Certainty

Overseeded Bermudagrass Options for annual bluegrass Kerb - 60 to 90 days (or charcoal) –Dimension – 6 to 8 wks –Barricade – 8 to 10 wks (supplemental label) –Balan – low rate, 6 weeks –Rubigan – cost limits use to greens –Prograss – greenup issue –TranXit and Revolver – 2 weeks before seeding

Poa Control with Kerb Excellent for annual bluegrass Will move with water and damage cool-season grasses Kerb movement onto bentgrass

Annual Bluegrass Control Bentgrass Greens paclobutrazol (Trimmit) at 0.25 lb/ac in the fall followed by 2 to 3 applications in the spring. Pre’s tend to select for the perennial type Poa annua

Roundup is effective Monument, Revolver, Katana are effective Kerb and Illoxan provides some control Reward and Finale ineffective Manor, Blade partial control Italian Ryegrass

Italian Ryegrass Control

Overseeding Clumpy perennial ryegrass Monument, Revolver, Katana

cool-season perennial Tall Fescue Roundup (risky) Kerb during winter months Corsair, Monument, Revolver, Certainty, Katana

Repeat applications of MSMA Usually 3 to 4 treatments required on a 5 to 7 day schedule Dallisgrass

Dallisgrass – New Option Apply MSMA at normal rate Follow 2 weeks later with spot treatment of Revolver at 1.0 fl. oz/gallon Follow 7 to 10 days later with MSMA at normal rate

Roundup Rate and Bermudagrass Control

Bermuda Control with Roundup – 1 yr.

Bermuda Suppression in Zoysiagrass Acclaim Extra –20.0 fl. ozs./acre –Apply every 4 weeks during growing season Fusilade II –3.0 to 4.0 fl. ozs./acre –Apply every 4 weeks during growing season Tank-mix with Turflon Ester at 1.0 qt./acre will improve control

Bermuda Suppression in Tall Fescue Apply 4 to 5 applications per year of Acclaim Extra at 20.0 fl. ozs./acre. Add Turflon Ester at 1.0 qt./acre to improve control. Apply every 4 weeks. Apply 2 applications (spring + fall) of Fusilade II at 5 to 6 fl. ozs./acre per year for 2 years

Bermuda Suppression in Centipedegrass Apply 2 applications (spring + 3 to 4 wks) of Vantage at 2.25 pts./acre per year for 2 years Apply 2 applications (spring + 3 to 4 wks) of Envoy at 34 fl. ozs./acre per year for 2 years (sod farm label)

Bermuda Suppression in St. Augustinegrass Prograss + Atrazine (2.0 gals qts./acre) 2 to 3 applications –1 st – 2 to 3 wks after spring growth resumes –2 nd – 30 days later –3 rd - 30 days later if regrowth occurs Temp. injury and stunting to St. Aug. will occur Avoid spray overlap or injury will increase

rhizome seedhead Bahiagrass Repeat MSMA Manor, Blade rhizomes

* 214 weed species *575 color photos *Control info for each weed $95.00

Turfgrass Web Page or.orgwww.georgiaturf.com 437 photographs of 193 weeds Control recommendations Popular articles Links to turfgrass organizations, GA automated weather network