Southeast Winter Weeds & Their Control ATA RoadShows: Scott Wanzor: Sales Representative : GA,AL,MS

Transcription

1 Southeast Winter Weeds & Their Control 2018 ATA RoadShows: Scott Wanzor: Sales Representative : GA,AL,MS swanzor@pbigordon.com

2 Purpose Of This Presentation: Learn to identify some common - and a few not-socommon - winter weeds in dormant warm season turf Help to understand the identification of certain weeds, especially several look-alike weeds, and why this is important Note some key, easy to identify characteristics of certain winter weeds Learn why it is important to properly identify weeds prior to trying to control them with herbicides and other methods Better understand the key differences between cool/cold weather weeds and warm weather weeds and why this is important Understand why certain types of herbicides work better on certain weeds Have a bit of fun doing it!

3 Calibration 1 gallon of water covers how many square feet?

4 Calibration: Backpack Know your water volume per 1,000 ft 2 Always double check rates of pesticide Correct Example (Slide 1 of 2 slides ) Label says to apply 3 oz. 1,000 ft 2 : - Amount of water you apply per 1,000 ft 2 = 2 gallons - 3 gallon backpack sprayer - Will cover 1,500 ft 2 (3 gals water divide by 2 gals/1,000 ft 2 ) - Therefore: Mix 4.5 oz. of herbicide in this backpack (3 oz./1,000 ft 2 x 1,500 ft 2 or 3 x 1.5)

5 Calibration: Backpack Incorrect example: (Slide 2 of 2 slides ) Label calls for 3 oz./1,000 ft 2-3 gallon backpack sprayer - You mix 3 oz. x 3 gallons of water (3 oz. for each gallon of water) - 9 oz. of herbicide Correct amount of herbicide is 4.5 oz. per 3 gallons. 9 oz. is double the rate on the label! 1) Excellent weed control! 2) Off label use! 3) Paid twice too much $$$!

6 Sisyrinchium rosulatum Winter annual NOT a grass: Iris family Flowers give it away Leaves clustered at crown Annual Blue-Eyed Grass Grass herbicides ineffective Use broadleaf herbicide! Not that difficult to control

7 Annual Blue-Eyed Grass

8 Dichodra carolinensis Creeping perennial: Roots nodes Confused with Dollarweed Leaf petiole not in center of leaf Not on many herbicide labels Repeat apps 3 and 4-way herbicides work well: Dichondra not on many labels. Adding MSM helps. Use care on St. Aug. and Centipede Dichondra

9 Soliva sessilis Winter annual Fruits with sharp spines Confused with Parsley Piert Leaves opposite, hairy Fairly easy to control: 3 and 4- way herbicides, MSM, others Lawn Burweed

10 Aphenes microcarpa Winter annual Confused with Lawn Burweed Leaves alternate, sparsely hairy, narrow lobes Fairly easy to control: 3 and 4- way herbicides, MSM, others Parsley Piert

11 Lawn Burweed vs. Parsley Piert

12 Hypochoeris radicata Perrenial Confused with Carolina False Dandelion, Dandelion, Asiatic Hawksbeard Taproot, milky sap (all above) Both sides leaf very bristly hairy Not difficult to control with 3 and 4-way herbicides, 2 apps Catsear Dandelion

13 Catsear Dandelion

14 Geranium carolinianum Winter annual or biennial Leaves and long petioles very hairy, red purple mixed with green Distinctive roundish cut leaves Can be tough to control Katana or repeat apps of 3 or 4- way herbicides. Add MSM helps. Carolina Geranium

15 Lamium amplexicaule Winter annual Confused with Purple Deadnettle Greenish purplish square stems Petioles on lower leaves. No petioles on upper leaves (whorled). Spring red-purple leaf. Good control with 3-4 way herbicides, Katana, MSM, etc. Henbit

16 Lamium purpureum Winter annual Confused with Henbit Greenish purplish square stems Lower leaves short petioles. Upper leaves longer petioles. Slightly more difficult to control than Henbit with 3-4 way herbicides, Katana, MSM, etc. Purple Deadnettle

17 Purple Deadnettle vs. Henbit

18 Poa annua Winter annual, bunch growth Extremely common, widespread Large membranous ligule Distinctive seedhead Can be extremely difficult to control: Herbicide resistance! Control: Post: Katana, Monument, Revolver, Kerb, atrazine. Pre: Indaziflam, prodiamine, simazine. Annual Bluegrass

19 Annual Bluegrass

20 Veronica persica Winter annual Very similar to Corn Speedwell Leaves much larger on Persian Speedwell. Flowers very similar: Larger on Persian Speedwell Control: Repeat applications of 3 and 4-way herbicides Persian Speedwell

21 Veronica arvensis Winter annual Very similar to Persian Speedwell Leaves much smaller on Corn Speedwell. Flowers very similar: Smaller on Corn Speedwell Healthy lawn usually chokes it out Control: Multiple applications of 3 and 4-way herbicides! Difficult! Corn Speedwell

22 Facelis retusa Winter annual Underside leaves, stems, appear white with soft matted hairs Top of leaves dull to bright green with tip spoon-shaped with point Spring flowers form white fuzz from dandelion-ish flowers 3 and 4-way herbicides work well Trampweed

23 Gnaphalium spicatum Annual or biennial Often confused with other cudweeds, esp. Purple Cudweed Top of leaves shiney bright green. Bottom of leaves dense white hair. Control: Difficult, slow. Leaves die close to crown first, then apex. Several weeks to fully die. Mult. apps 3 and 4-way herbicides, MSM. Shiny Cudweed

24 Gnaphalium purpureum Annual or biennial Often confused with other Cudweeds, esp. Shiny Cudweed Underside of leaves soft, velvetlike white hair. Upper side of leaves less hairy, dull green. Control: Difficult, slow. Leaves die close to crown first, then apex. Several weeks to fully die. Mult. apps 3 and 4-way herbicides, MSM. Purple Cudweed

25 Shiny vs. Purple Cudweed

26 White Clover Trifolium repens Perrenial Confused with Yellow Woodsorrel Flower white, pink tinge, round aggregate round head Leaves often with white band partly encircling base each leaflet Control: 3 and 4-way herbicides work well. Katana. MSM, others.

27 Yellow Woodsorrel & Creeping Woodsorrel Oxalis stricta Herbaceous perennial Confused with White Clover (Burr Clover, Hop Clovers, Black Medic) Usually lighter green leaves Bright yellow 5-petal flower Control: Repeat apps. 3 and 4- way herbicides, Katana, MSM, etc. Oxalis corniculata Herbaceous perennial Dark green to deep purple leaves Stolons readily root at nodes Bright yellow 5-petal flower Control: Repeat apps. 3 and 4- way herbicides, Katana, MSM, etc. Reportedly more difficult to control than O. stricta.

28 Cardamine hirsute Winter annual Very common, widespread Leaves form a tight rosette pattern of deeply lobed leaves. Leaves higher up on stems look very different from basal leaves. Bunches of small white flowers in spring. Prolific seed producer. 3 and 4-way herbicides work well: Use prior to flowering to stop seeds. Hairy Bittercress

29 Stellaria media Winter annual Forms dense mats of plants Smooth leaf surfaces Prefers at least some shade Control: Easy to control with most post emergent herbicides Common Chickweed

30 Cerastium vulgatum Winter annual (Perrenial in mountains) Freely roots at nodes Densely hairy leaves and stems White flower similar to Common Chickweed Control: Easy to control with most post emergent herbicides 0.25% v/v surfactant helps control Mouse-ear Chickweed

31 Sherardia arvensis Winter annual Leaves whorled, sparsely hairy Square stems Tiny pink or lavender flowers Control: Repeat apps. 3 and 4- way herbicides Field Madder

32 Wild Garlic Allium vineale Cool season perennial Often confused with Wild Onion Wild Garlic has hollow stem. Wild Onion has solid stem. Produces offset flattened bulblets that are enclosed by brown skin. Each will form a new bulb, plant. Control: 3 and 4-way herbicides moderately effective mult. apps. Katana, Monument, MSM excellent. *Add 0.25% surfactant waxy leaf

33 Wild Garlic: What s Going On Underground?

34 Bermudagrass Dormancy Notes: Bermuda stops growing <60-65 o Begins dormancy process <50 o Bermudagrass has two phases of dormancy: > Phase 1: Grass blades turn tan and die when temperatures drop into the upper 20 s > Phase 2: Stolons begin to die with prolonged colder temps, usually teens or lower Black road surface retains heat Curb retains heat from sun Blades dead, stolons still alive Not completely dormant

35 Southeast Winter Weeds & Their Control 2018 RoadShows: Scott Wanzor: Sales Representative : GA,AL,MS swanzor@pbigordon.com