Weed, Insect, and Disease Control for Turfgrass Producers Preview

Weed, Insect, and Disease Control FOR TURFGRASS PRODUCERS

FIRST EDITION, 2022

Editor Casey Reynolds, PhD. Executive Director, Turfgrass Producers International

Authors Matthew Elmore, PhD. Assistant Extension Specialist, Weed Science. Rutgers University Gerald (Lee) Miller, PhD. Associate Professor, Turfgrass Pathology. University of Missouri Aaron Patton, PhD. Professor, Turfgrass Extension Specialist. Purdue University Doug Richmond, PhD. Professor and Extension Specialist, Turfgrass Entomology and Applied Ecology. Purdue University Casey Reynolds, PhD. Executive Director, Turfgrass Producers International Manuel Roman Chavarria Sanchez, PhD. Lead Research Scientist. Prairie Turfgrass Research Centre, Alberta Canada

Acknowledgements April N. Grummer, Undergraduate Student, Department of Entomology. Purdue University Daniel Earlywine, Research Assistant, Turfgrass Pathology. University of Missouri

This free publication is created and mailed annually to members of Turfgrass Producers International.

For more information on this and other TPI member benefits, please visit www.TurfgrassSod.org.

TABLE OF CONTENTS

What’s New for 2022 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Interpreting Product Labels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Tips for Maximizing Sprayer Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Weeds Weed management in turfgrass production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Herbicide Mode of Action (MOA) classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Herbicides for control of grassy and broadleaf weeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Preemergence herbicides for grassy and broadleaf weeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Application timing restrictions of preemergence herbicides at various stages of sod production . . . . . . 14 Selective postemergence herbicides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Synthetic auxin postemergence herbicides for broadleaf weeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Product formulations containing synthetic auxin herbicides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Alternatives to synthetic auxin herbicides for postemergence broadleaf weed control . . . . . . . . . . . . . . . . . . 32 Nonselective herbicides for general weed control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Herbicides for commonly occurring weeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Crabgrass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Sandbur . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Annual Bluegrass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Bermudagrass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 Nutsedge and Kyllinga . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 Herbicides containing sulfentrazone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Herbicides containing quinclorac. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Turfgrass tolerance to postemergence herbicides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Herbicides authorized for use in various countries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Insects Arthropod pests of turfgrass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 Insecticide Mode of Action (MOA) classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 Insecticides registered for use in turfgrass production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 Ants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 Aphids. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 Armyworms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 Billbugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 Chinch Bugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 Cicada Killers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 Crane Flies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 Cutworms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 Leafhoppers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 Mealybugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 Mites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 Mole Crickets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 Sod Webworms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 Spittlebugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 White Grubs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 Insecticides and miticides authorized for use in various countries. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Diseases Turfgrass diseases. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 Fungicide Mode of Action (MOA) classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 Fungicides registered for use in turfgrass production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 WARM-SEASON TURFGRASS DISEASES Large Patch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 Spring Dead Spot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 COOL-SEASON TURFGRASS DISEASES Anthracnose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 Brown Patch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 Damping Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 Dollar Spot. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 Fairy Ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 Gray Leaf Spot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 Leaf Spot/Melting Out. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 Michrodochium Patch (Pink Snow Mold) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 Pythium Blight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 Red Thread . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 Rust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 Summer Patch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

Nematodes in turfgrass. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 Fungicides authorized for use in various countries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

Plant Growth Regulators Benefits of plant growth regulators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 Types of PGRs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 Using PGRs successfully in turfgrass production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

What’s New for 2022 New Herbicides ✔ Celsius Xtra (thiencarbazone-methyl + iodosulfuron + halosulfuron). The sister product “Celsius” contains thiencarbazonemethyl + iodosulfuron + dicamba. The substitution of halosulfuron for dicamba means Celsius Xtra will control or suppress sedge species. ✔ Sublime (triclopyr + dicamba + mesotrione)

New trade names of herbicides with previously registered active ingredients and/or previously registered combinations of ingredients include: • Acquit (sulfentrazone) • Addax (asulam) • Antik EC (carfentrazone) • Aquesta 4F (sulfentrazone) • Biscayne (bentazon) • Cheetah Pro (glufosinate) • Daikon (halosulfuron + dicamba) • Doleac DMA (dicamba) • Dolerity DGA (dicamba) • Empero (halosulfuron) – not in OR or WA • Finale XL T&O (glufosinate) • Flumioxazin 51WDG Select (flumioxazin) • Meso 4SC Select (mesotrione) • Metallis (S-metolachlor) • Q-Ball (quinclorac) • Quintessential (quinclorac) • Semera 51WDG (flumioxazin) • Semera SC (flumioxazin) • Sertay (sulfosuluron) • SlipStream (mesotrione) – not in AZ • Stadia (halosulfuron) – not in OR or WA • Torocity (mesotrione) • Triad QC Select (2,4-D + quinclorac + dicamba) • Triad T Select (2,4-D + MCPA + triclopyr + dicamba) New trade names of plant growth regulators with previously registered active ingredients include: ✔ Pramaxis MEC (trinexapac-ethyl)

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What’s New for 2022

The U.S. Environmental Protection Agency (EPA) has proposed the following changes to oxadiazon in sod production. TPI is working with EPA on these changes and will share the results of the Final Decision when they occur. Proposed changes include: ✔ Use on turfgrass will be limited to golf course fairways and sod farms only ✔ Yearly maximum use rate to be reduced from 8 lb ai/A to 6 lb ai/A ✔ The single maximum application rate reduced from 4 lb ai/A to 3 lb ai/A ✔ Applications are limited to 2 per year – spring and fall ✔ Liquid applications will be limited to 1 per year ✔ There must be a 120-day retreatment interval between applications ✔ Application to sports fields is prohibited, included at planting/new construction

New Insecticides ✔ Fipronil 0.0143G, Fipronil 0.1G (fipronil) ✔ Suprado (novaluron) ✔ Alucion 35WG (dinotefuron + alpha-cypermethrin)

New Fungicide ✔ Serata (picarbutrazox): Only effective against Pythium diseases such as damping off, root rot, root dysfunction and blight.

Weeds

4

Weeds

Weed management in turfgrass production Weeds in turfgrass production fields increase production costs (e.g. equipment, herbicide, and labor costs) and reduce the inventory of marketable sod due to contamination (lost production ground) and lack of turfgrass uniformity (poor quality). All managed turfgrass systems (athletic, lawn, golf, sod) have weed problems, but production fields typically have different weed problems. While some common weeds are the same (crabgrass, nutsedge, spurge), often turfgrass production fields receive additional weed pressure from surrounding farm fields, open drainage ditches, fence rows, or previous crops. As such, controlling weeds in nearby fence rows and open drainage ditches is essential to keeping these problematic weeds out of production areas. Additionally, good sanitation (i.e. cleaning of equipment) can help prevent weeds from being introduced.

Turfgrass farms typically suffer more from annual weed problems than perennial weeds, with rhizome producing perennial grasses and nutsedge being exceptions. Annual weeds invade after harvest, germinating in bare soil left behind (Figure 1). Annual weeds are often easily controlled, particularly broadleaf weeds that invade shortly after harvest or planting. Many of these annual weeds are controlled simply through proper cultural practices of regular mowing while others may require the use of herbicides. Perennial grassy weeds with rhizomes, such as common bermudagrass, smooth brome, or quackgrass, are the most problematic and have the biggest impact on harvestable acreage.

Additionally, off-types of the desirable crop, such as common bermudagrass in a hybrid bermudagrass crop, are only removable through non-selective herbicide applications. Substantial effort should be placed towards the eradication of these perennial grassy weeds.

Protecting the Crop

Most modern herbicides that can be safely used on established turf can also be safely used in production fields. Some herbicides; however, can inhibit root or rhizome development which could run the risk of reducing sod tensile strength or reducing the rate that a crop fills-in after planting. Several herbicides may cause injury or impact sod tensile strength, but three specific herbicide modes of action should be used cautiously: WSSA Group 3 (HRAC K1), WSSA Group 5 (HRAC C1) and indaziflam, a WSSA group 29 (HRAC L) herbicide (Table 2).

Herbicides that inhibit microtubule assembly (WSSA Group 3, HRAC K1) and indaziflam reduce the ability of stolons and sprigs to root into the soil. This is most problematic when these herbicides are applied after harvest as recovery from sod ribbons can be reduced. As such, these herbicides are used less often in turfgrass production because of their potential to reduce rooting and establishment from either sprigs or stolons. Oxadiazon (Ronstar), a WSSA Group 14 (HRAC E) herbicide, is a potential alternative in sprigged bermudagrass or zoysiagrass. When seeding cool-season grasses such as tall fescue or Kentucky bluegrass, mesotrione (Tenacity; WSSA group 27, HRAC F2) is one of the few herbicides that can be applied to provide residual weed control without inhibiting seedling development.

Commonly used WSSA Group 5 (HRAC C1) herbicides include atrazine and simazine. These herbicides provide excellent weed control but can injure certain tolerant warmseason grass species such as hybrid bermudagrass. Injury often occurs when applied to immature sprigs and this can result in reduced sod tensile strength when herbicides are used at high label rates. Further, some cultivars may be less tolerant. Growers are advised to test the safety of these herbicides on new cultivars before treating large areas.

Figure 1. Bare soil between sod ribbons, such as in this zoysiagrass (Zoysia japonica) production field, provide a perfect opportunity for the invasion of annual weeds.

Weeds

5

Table 5. Postemergence herbicides for selective weed control in turfgrasses

Common name 2,4-D

Trade name (Product/A)

Turfgrasses labeled for application

Hardball (1–1.75 qt)

Cool-season: All major species

Weedar 64 (1-1.5 qt)

Warm-season: BA, BE, CE, Z

HRAC, WSSA group

Weeds controlled

Comments

Broadleaf weeds

Do not apply to St. Augustinegrass. Can be applied to centipedegrass and bentgrass on sod farms only.

Short-term stunting may result from application to centipedegrass and bentgrass, especially at higher rates. Many products permit application to bentgrass only as a spot treatment.

Others

O, 4

Do not apply to newly seeded turfgrass until it has been mowed at least twice. Do not seed into treated area until at least 30 days after application.

Many broadleaf weeds are not controlled by 2,4-D alone.

For more broad-spectrum control, combine with other active ingredients such as dicamba, triclopyr, or fluroxypyr.

Rates and recommended turf species differ for sod.

2,4-D + dicamba

On Deck (1-4 qt)

Cool-season: CBG, KB, PR, TF

Broadleaf weeds

Warm-season: BA, BE, CE, BU, SS, Z 2,4-D + dichlorprop

Patron 170 (3.5 qt)

Cool-season: All major species

Control a broader spectrum of weeds than 2,4-D alone. Do not apply more than 1.5 pt/A to warm-season turfgrass.

O, 4

For use on creeping bentgrass only as a spot treatment.

Many broadleaf weeds

Controls a broader spectrum of weeds than 2,4-D alone.

O, 4

Many broadleaf weeds

Provides broad-spectrum broadleaf weed control.

Provides excellent white clover and Canada thistle control.

O, 4

Warm-season: BE, BU, CE, SA, Z 2,4-D + clopyralid + dicamba

Millennium Ultra 2 (1.5–3 pt)

Cool-season: All major species Warm-season: BA, BE, Z

2,4-D + dicamba + quincloraz

2DQ (1–4 pt)

Cool-season: All major species except FF

Specifically for common bermudagrass; use on hybrid bermudagrass not specified. Short-term injury may occur after application to creeping bentgrass where lower rates are specified on the label.

Many broadleaf weeds

Warm-season: BA, BE, CE, SA, Z 2,4-D ester + mecoprop + dicamba + pyraflufen-ethyl

Redzone 2 (1.8–4 pt)

2,4-D ester + triclopyr ester + dicamba + pyraflufen-ethyl

4 Speed XT (1.8–4 pt)

Cool-season: All major species

Provides broad-spectrum broadleaf weed control. Use lower rates in warm-season turfgrass. Short-term injury may result after application to Centipedegrass or St. Augustinegrass especially if applied during spring greenup.

O, 4

Higher rates (up to 4 pt/A) can be used in cool-season turfgrass sod production.

Many broadleaf weeds

Some hybrid bermudagrass varieties may be sensitive.

Use lower rates in creeping bentgrass to prevent injury.

O, 4

Many broadleaf weeds

Some hybrid bermudagrass varieties may be sensitive.

Use lower rates in creeping bentgrass to prevent injury.

O, 4 + E, 14

Warm-season: BA, BE, Z Cool-season: All major species Warm-season: BA, BE, Z

continued on next page

Weeds

17

Table 7 continued. Nonsynthetic auxin herbicides for postemergence broadleaf weed control in turfgrasses

Common name

Trade name (Product/A)

sulfentrazone + carfentrazone

Dismiss NXT (5.1 to 15.2 oz) Spartan Charge (5.1 to 10.2 oz)

sulfentrazone + metsulfuron - methyl

Blindside (3.25–10 oz)

Turfgrasses labeled for application

HRAC, WSSA group

Weeds controlled

Comments

Most cool- and warm-season grasses (see label).

Broadleaf weeds, sedges/kyllingas

Spartan Charge is labeled for sod production only.

Primarily functions as a contact herbicide. Tank-mix with systemic herbicides to control perennial or mature annual weeds.

E, 14

Cool-season: KB, TF,

Broadleaf weeds, some grasses, sedges

Provides good to excellent control of many broadleaf weed species.

E, 14 + B, 2

Warm-season: BE, BU, CE, SA, Z

A systemic herbicide with some soil residual.

Use caution around trees and ornamental plants.

See label for more information.

Sulfentrazone results in injury symptoms visible within 48 hours, compared to about 2 wk for metsulfuron-methyl alone.

thiencarbazone - methyl + iodosulfuron + dicamba

Celsius WG (2.5–4.9 oz)

Cool-season: None Warm-season: BE, BU, CE, SA, Z

Broadleaf, grassy weeds

Controls many broadleaf weeds.

Two applications may be needed for difficult-to-control weeds such as dichondra, wild geranium, and Virginia buttonweed.

B, 2 + O, 4

Nonselective herbicides for general weed control Table 8. Nonselective herbicides for general weed control and/or turfgrass renovations HRAC, WSSA group

Trade name (Product/A)

Comments

dazomet

Basamid (218–525 lb)

See label regarding site preparation, use rates, tarping and overhead irrigation after application.

Tarping may improve efficacy. Restricted-use pesticide.

Z, 17

diquat

Reward (1–2 pt)

Quickly dries out green tissues. Adequate spray volume is essential to obtain leaf coverage and best control. A contact herbicide that does not translocate and therefore does not control perennial weeds.

D, 22

glufosinate

Finale (3–6 qt)

Translocation more limited than that of glyphosate; thus, it is excellent for edging around desirable turfgrass. Can be applied to dormant bermudagrass.

H, 10

glyphosate

RoundUp, Touchdown, many others (see label)

Optimal for control of grasses and many broadleaf plants. At low rates, does not completely control legumes or Cyperaceae (sedges and kyllingas).

G, 9

glyphosate + 2,4-D

Campaign (1.5 to 4.0 pt)

Consider tank-mixing with additional glyphosate to control certain weeds. See label.

G, 9 + 0, 4

pelargonic acid

Scythe (see label)

Dries out green tissues quickly. Spray volume must be adequate to obtain leaf coverage and best control. Does not translocate or control perennial weeds.

Z, 17

Common name

Weeds

33

Herbicides for commonly occurring weeds Crabgrass

Preemergence herbicides

Most preemergence herbicides in the section on preemergence herbicides for grassy and broadleaf weeds (table 3; beginning on page 9) provide acceptable crabgrass control when applied before crabgrass germination.

However, most of these should not be applied to immature turf often present in sod production. See table 4, (intervals for preemergence herbicides application in sod production) for more information. Mesotrione is commonly used for annual weed control on immature seeded cool-season turfgrass species while oxadiazon is commonly used on immature sprigged warm-season species.

Crabgrass germination typically occurs in late winter to mid-spring (February to mid-May depending on location), but varies from year to year, based on temperature, rainfall, and location. Crabgrass germination usually begins when the soil temperature at a 2-inch depth reaches 55°F for at least 3 days in temperate climates. Germination may occur throughout the year in tropical climates.

The forsythia (Forsythia spp.) plant can be used to time preemergence herbicide application. Make preemergence applications when forsythia are in full bloom (since they are usually among the first plants to bloom, their yellow flowers are easy to spot). Forsythia plants are most prevalent in the eastern United States.

Postemergence herbicides

These herbicides control crabgrass plants at various growth stages after germination. See the comments section and the product label for efficacy and application rates at various growth stages. Most products in table 9 control smooth (Digitaria ischaemum) and large (Digitaria sanguinalis) crabgrass. Control may vary for other crabgrass species, such as blanket (D. serotina), India (D. longiflora), and tropical (D. bicomis) crabgrass.

If you apply herbicides early in the season in areas where the desirable turfgrass is thin and crabgrass infestations are severe, new crabgrass plants will germinate in the voids after the existing crabgrass plants are controlled. For residual control, consider tank-mixing a preemergence herbicide with the postemergence herbicides in table 9.

Large crabgrass (Digitaria sanguinalis) and common bermudagrass (Cynodon dacytlon) contamination of a zoysiagrass (Zoysia japonica) production field. Repeated spot applications of glyphosate are needed to remove perennial weeds costing labor and chemical and resulting in reduced harvestable acreage. In this photo, the common bermudagrass was sprayed with glyphosate once already but additional applications are necessary for removal.

34

Weeds

Insects

56

Weeds

Arthropod pests of turfgrass Although the small, multi-segmented animals found associated with turfgrass sod are often referred to collectively as insects, these organisms actually represent a larger, more diverse group of animals known as arthropods (insects, mites, spiders, centipedes, millipedes, crayfish, etc.).

Many different arthropods are associated with sod, but a handful of common species are responsible for the vast majority of damage.

A square yard of healthy turfgrass typically contains thousands of arthropods, most of which are beneficial.

These animals perform a variety of important functions including decomposition of dead plant material necessary for proper nutrient cycling, soil aeration that enhances water and nutrient infiltration, natural control of insect pests through predation or parasitism, and pollination of flowering plants and food crops. The primary challenge for turfgrass producers then, is striking a balance between the functional, aesthetic and economic requirements of the sod that make it harvestable and marketable, and maintaining an environment that is suitable for beneficial organisms and the stabilizing ecological services they provide.

Integrated pest management

Sound cultural practices that promote healthy, vigorous turfgrass capable of tolerating or quickly recovering from arthropod damage form the foundation of an approach called “integrated pest management” (IPM). The goal of IPM is not to eliminate arthropods, but to manage those few species that are pests in order to keep them below damaging levels. When properly implemented and aligned with user needs and expectations, IPM can achieve grower goals while minimizing pesticide use, reducing costs and environmental impacts, and increasing worker safety. Only when the balance between beneficial organisms and pests is disrupted are growers usually forced to take remedial action.

Such actions often involve the use of biological or synthetic insecticides.

Because efficient insecticide use requires proper targeting, timing and product selection, some basic knowledge of pest identification and biology is useful. There are many resources available that provide this information including: county and state extension specialists, consultants, extension publications, textbooks, and videos. In order to effectively scout for pests and select an appropriate product for a specific pest problem, growers should also think about pests in terms of the different regions of the sod profile where they are likely to be found. The location of the pest within this profile and the stage of development the pest has reached will determine the kinds of scouting approaches that are likely to reveal the pest and inform the grower’s choice of insecticide chemistry, formulation, and application techniques.

The target zone

For the purposes of scouting and applying insecticides, turfgrass arthropod pests can be categorized into two broad groups: surface-dwelling and soil-dwelling. Although this distinction can seem a bit artificial for pests that spend portions of their life in both zones, the choice of target, adult vs larva for instance, can determine the utility of a given scouting procedure and the efficacy of a given insecticide application.

Surface-dwelling pests like billbug adults, cutworms, armyworms, chinch bugs and aphids are typically exposed to insecticide residues by ingesting or contacting treated surfaces (i.e., leaf tissue or thatch). A broad selection of insecticides are suitable for this kind of application as long as they adhere to material that the target pest will contact or ingest. Movement through the thatch and into the soil is not necessarily required for good efficacy and may in fact reduce the residual efficacy of the application by moving it away from the zone where the target pest is most active. However, uptake of systemic insecticides through the roots, and movement upward into above-ground tissues (translocation) can enhance and prolong the residual efficacy of some products (i.e., neonicotinoids and anthranilic diamides). Direct penetration of plant tissues by translaminar products can serve a similar purpose. Translocation or translaminar movement may in fact be essential when the target pest is located within plant tissues where it is not directly exposed to insecticide deposits on the treated surfaces (e.g., billbug larvae tunneling within plant stems). For arthropod pests like ants, that are active on the surface, but do not directly feed on plants, bait formulations may also be effective.

Soil-dwelling pests such as white grubs are typically exposed to insecticides only after the product has moved through the thatch and into the soil where the pest is active.

“Sticky” materials, like pyrethroids, that bind tightly to organic matter at the soil surface rarely move into the soil in large enough amounts to be effective against such targets.

Conversely, more water-soluble materials move readily into the soil where the pest is active. This process can be facilitated by precipitation or irrigation immediately following the application. Once in the soil, such materials may be taken up by the plant as a sort of self-protection, or simply contacted and ingested by the target pest.

Management decision guide

The following tables are provided to help turfgrass producers prioritize monitoring programs based on the frequency and damage potential of the arthropod, and select appropriate insecticides based on the target, mode of action, and the spectrum of activity of a particular formulation. These tables include only chemical insecticides registered for use in sod production. In order to prolong the useful lifespan of chemical insecticides, a rotation that includes multiple classes and modes of action is always the best practice.

Insects Weeds

57

Table 1. Arthropod pests of turfgrass, target zones and relative importance in turfgrass production Common name

Scientific name

Target Zone

Frequency

Damage potential

Ants

Several species

soil and surface

Common

Low to High

Aphids (Greenbug)

Schizaphis graminum

surface

Occasional

Moderate

Armyworms

Several species

surface

Common

Moderate

Billbugs

Sphenophorus spp.

soil and surface

Common

High

Chinch bugs

Blissus spp.

surface

Common

High

Cicada killers

Sphecius spp.

soil and surface

Occasional

Low

Crane flies

Tipula spp.

soil

Occasional

Moderate

Cutworms

Several species

surface

Occasional

Moderate

Leafhoppers

Several species

surface

Occasional

Moderate

Mealybugs

Several species

surface

Occasional

Moderate

Mites

Several species

surface

Occasional

Moderate

Mole crickets

Several species

soil

Common

High Moderate

Sod webworms

Several species

surface

Common

Spittlebugs

Prosapia spp.

surface

Occasional

Moderate

White grubs

Several species

soil

Common

High

No products currently registered for ground pearls, scales or yellow jackets on sod farms

Insecticide Mode of Action (MOA) classification Table 2. Mode of action classifications of chemical1 insecticides and miticides registered for use in turfgrass production (Source: IRAC) Products containing a single active ingredient Common name

Trade name

Mode of Action (MOA)2

Subgroup (Class)

IRAC2 Code

acephate

Acephate 90% Prills, Acephate 97 UP, Acephate 97 WDG, Bracket 97, Bracket 97 WDG, Orthene T-T&O WSP, Orthene T-T&O 97

Acetylcholinesterase inhibitors

Organophosphates

1B

bifenthrin

Avalon Golf & Nursery, Bifen 2 AG Gold, Brigade 2EC, Capture LFR, Fanfare ES, Menace GC 7.9% F, Pro-Mate Bifenthrin, Sniper, Tailgunner, Talstar GC, Talstar S, Up-Star GC, Up-Star SC, Wisdom GC

Sodium channel modulators

Pyrethroids

3A

carbaryl

Carbaryl 4L, Sevin SL

Acetylcholinesterase inhibitors

Carbamates

1A

chlorantraniliprole

Acelepryn SC, Acelepryn G

Ryanodine receptor modulators

Diamides

28

chlorpyrifos

Chlorpyrifos 4E, Chlorpyrifos 4E-AG, Dursban 50W, Govern 4E, Hatchet, Lorsban 4E, Lorsban Advanced, Vulcan, Warhawk, Whirlwind, Yuma 4E

Acetylcholinesterase inhibitors

Organophosphates

1B

clothianidin

Arena 0.25 G, Arena 50 WDG

Nicotinic acetylcholine receptor agonists

Neonicotinoids

4A

cyantraniliprole

Ference SC

Ryanodine receptor modulators

Diamides

28

deltamethrin

Deltagard GC

Sodium channel modulators

Pyrethroids

3A

dicofol

Dicofol 4E

Uncertain mode of action

Dicofol

dinotefuran

Zylam Liquid, Zylam 20 SG

Nicotinic acetylcholine receptor agonists

Neonicotinoids

Unknown 4A continued on next page

58

Insects

Insecticides registered for use in turfgrass production Table 3. Insecticides registered for control of Ants in turfgrass production

Common name

Trade name

acephate

Acephate 90% Prills Acephate 97 UP Acephate 97 WDG Bracket 97 Bracket 97 WDG Orthene T-T&O WSP Orthene T-T&O 97 Avalon Golf & Nursery

bifenthrin

Bifen 2 AG Gold Brigade 2EC Capture LFR Fanfare ES Menace GC 7.9% F Pro-Mate Bifenthrin Sniper Tailgunner Talstar GC Talstar S

Product/A

10-40 fl oz

Product/ 1000 ft2

0.25-1 fl oz

7-14 fl oz 7-14 fl oz 100-200 lb 10-40 fl oz

0.16-0.32 fl oz 0.16-0.32 fl oz 0.2-0.4 fl oz 0.16-0.32 fl oz 1 fl oz 0.5-1.0 fl oz 0.16-0.32 fl oz 0.16-0.32 fl oz 2.3-4.6 lb 0.25-1 fl oz

Up-Star GC Up-Star SC

100-200 lb 10-40 fl oz

2.3-4.6 lb 0.25-1 fl oz

Wisdom GC Carbaryl 4L Sevin SL Chlorpyrifos 4E Chlorpyrifos 4E-AG Dursban 50W Govern 4E Hatchet Lorsban 4E Lorsban Advanced Vulcan Warhawk Whirlwind Yuma 4E Arena 0.25 G Arena 50 WDG Deltagard GC Zylam Liquid Zylam 20 SG Chipco Choice Maxforce FC

100-200 lb 2-4 qt 2-4 qt 1 qt 1 qt 2 lb 1 qt 1 qt 1 qt 1 qt 1 qt 2 pt 1 qt 1 qt 120-160 lb 9.6-12.8 oz 87-131 lb 4.9 pt 2.7 lb 12.5 lb 1.5-5 lb

2.3-4.6 lb 1.5-3 fl oz 1.5-3 fl oz 0.75 fl oz 0.75 fl oz

0.22-0.29 oz 2-3 lb 1.8 fl oz 1 oz 4.6 oz 0.5-1.83 oz

hydramethylnon

Topchoice Maxforce Complete Amdro Pro

87 lb 1.5 lb 1-2 lb

2 lb 0.56 oz 0.4-0.8 oz

indoxacarb

Advion Fire Ant Bait

1.5 lb

carbaryl chlorpyrifos

clothianidin deltamethrin dinotefuran fipronil

7-14 fl oz 8.7-17.42 fl oz 7-14 fl oz 40 fl oz

IRAC Code

Notes Mound drench treatment (see label) for fire and harvester ants only.

Mound drench treatment (see label) for fire and harvester ants only.

Mound drench treatment (see label) for fire and harvester ants only.

Mound drench treatment (see label) for fire and harvester ants only.

Mound drench treatment (see label) for fire and harvester ants only.

Drench (see label) and dry (1-2 tsp) mound treatments for imported fire and harvester ants only.

Mound drench treatment (see label) for fire and harvester ants only.

Broadcast treatment rate varies by species.

Annual application rate of 40 fl oz/A

1B

3A

Rate varies by usage strategy

Broadcast treatment rate varies by species.

Annual application rate of 40 fl oz/A Broadcast treatment rate varies by species.

Annual application rate of 40 fl oz/A 1A 1B

0.75 fl oz 0.75 fl oz 0.75 fl oz 0.75 fl oz 0.75 fl oz 0.75 fl oz 0.75 fl oz 0.75 fl oz Nuisance ants only Not for fire, harvester, Pharaoh, or carpenter ants

4A

Not for fire ants Not for fire, harvester, Pharaoh, Argentine, or carpenter ants Imported Fire Ants only Imported Fire Ants only. Broadcast treatment.

Mound treatments of 2-5 tbsp or 1.5-5 lb Broadcast treatment. Mound treatments of 2 tbsp or 1 oz Broadcast treatment rate varies by species.

Mound treatments of 2-5 tbsp Broadcast treatment. Mound treatments of 4 tbsp

3A 4A 2B

20A

22A

continued on next page

60

Insects

Hunting Billbug Beak

Larval (grub) and adult (weevil) stages of a billbug. At least 6 species are known to infest turfgrass sod. Billbug adults have a distinctive snout that is characteristics of weevils and is used for insertion and feeding in plant stems. However, damage from adults is rare and usually not significant. Most of the damage occurs as larvae (white, legless, with brown head capsule) feed on stems, crowns, roots, stolons and rhizomes resulting in spotty, brown patches of sod. (Pictured: Hunting Billbug Sphenophorus venatus)

Table 6 continued. Insecticides registered for control of Billbugs in turfgrass production Product/ 1000 ft2

Notes

Battle GC 10 fl oz Lambda-Cy EC 8.8 fl oz Lambda Select 8.8 fl oz Nufarm LambdaCyhalothrin 1 EC 8.8 fl oz Scimitar GC 10 fl oz Quali-Pro Lambda GC-O 10 fl oz Meridian 0.33 G 60-80 lb Meridian 25 WG 12.7-17 oz

7 ml 6 ml 6 ml

Bluegrass billbug adults only Bluegrass billbug adults only Bluegrass billbug adults only

6 ml 7 ml 7 ml 1.4-1.8 lb 0.3-0.4 oz

Bluegrass billbug adults only Bluegrass billbug adults only Bluegrass billbug adults only Larvae only Larvae only

bifenthrin + zeta-cypermethrin

Talstar Xtra GC

50-100 lb

1.15-2.3 lb

Adults only

clothianidin + bifentrin imidacloprid + bifenthrin

Aloft GC G Aloft GC SC Allectus GC SC

80-160 lb 11.65-23.3 fl oz 2.3-4.5 pt

1.8-3.6 lb 0.27-0.54 fl oz 0.9-1.65 fl oz

3A, 4A

imidacloprid + bifenthrin + zeta-cypermethrin

Triple Crown Golf

25-35 fl oz

0.57-0.8 fl oz

3A, 4A

Common name

Trade name

lambda-cyhalothrin

thiamethoxam

Product/A

IRAC Code 3A

4A 3A

3A, 4A

* See label for detailed instructions.

Insects

65

Diseases

82

Insects

Turfgrass diseases Infectious disease occurs when three factors integrate simultaneously – a susceptible host, a virulent pathogen, and a conducive environment. Like humans, turfgrasses are more susceptible to infection when not healthy and actively growing. Plants are more likely to contract a disease when continuously exposed to abiotic environmental stressors (i.e. heat, drought or flooded conditions, etc.), or stresses invoked by high or improper maintenance practices (i.e. low mowing height, lack or excessive fertility, overirrigation, etc.). Growing the right plant (turfgrass species and cultivar) in the right place under the right conditions will limit or prevent turfgrass disease occurrence.

Turfgrass management involves growing individuals of the same or similar genotype very close together, meaning pathogen dissemination and disease transmission is relatively easy and occurs quickly. Therefore, even under proper management, fungicides may be necessary and are recommended for protection of high amenity turfgrasses.

Correct and judicious fungicide use requires knowledge of the biology of the pathogen, including where the pathogen infects the plant and the environmental conditions required for infection. These two factors greatly influence the necessary methods for fungicide delivery and application timing to maximize disease control.

Fungicide Delivery: Different pathogens can infect different parts of the plant. Foliar pathogens cause diseases such as brown patch and pythium blight and infect leaves and sheaths. The location of infection for soilborne diseases such as spring dead spot or summer patch is stolons, rhizomes or roots. Fungicides must be effectively delivered to the location of infection. This is particularly crucial for soilborne diseases because most fungicides move upward in the plant, and will not move downward into the rootzone to a depth greater than they are applied. Therefore, fungicides targeting soilborne diseases must be either applied in higher carrier volumes

Table 1. Location of infection for turfgrass diseases

FOLIAR

ROOTS, STOLONS, RHIZOMES

Anthracnose

Fairy Ring

Brown Patch

Nematodes

Dollar Spot

Spring Dead Spot

Gray Leaf Spot

Summer Patch

Large Patch

(3-5 gallons/1000 sq ft) or, perhaps more effectively, be watered in with at least 1/8 inch (3 mm) of postapplication irrigation.

Application Timing: Preventing disease and turfgrass loss often relies on applying fungicides not when symptoms occur, but earlier in the disease cycle when infection occurs. As with fungicide delivery, this is particularly true for control of many soilborne diseases which can infect and cause root loss prior to symptom development. For instance, the spring dead spot pathogen infects and inhibits the bermudagrass’ ability to overwinter in the fall before symptoms ever appear the following spring.

Therefore, fall and not spring applied fungicides are necessary for effective control of this disease. Several foliar diseases, such as dollar spot and pythium blight, can cause symptoms rapidly, and are also most effectively controlled preventively. See each disease description for information regarding timing.

Fungicide Resistance: As with other pests, pathogen populations can develop resistance to fungicides when exposed to repeated applications. In many cases, the population doesn’t just contract resistance to the one fungicide active ingredient or product that’s been used, but will also acquire resistance to all the fungicides that are in that class or mode of action. Therefore, rotating fungicide classes for pathogens that are known to develop resistance is critical to a long-term control strategy. This being said, not all turfgrass pathogens have the same propensity to develop resistance. Take brown patch for instance. Despite repeated applications targeting this disease, no instances of fungicide control failure of brown patch have been observed due to fungicide resistance.

Below is a table listing turfgrass pathogens and fungicide classes with known cases of fungicide resistance.

Table 2. Turfgrass diseases with known cases of fungicide resistance Disease

Chemical Class

Anthracnose

Benzimidazoles DMIs Strobilurins (QoI) Benzimidazoles Dicarboximides DMIs SDHI Strobilurins (QoI) Phenylamides Benzimidazoles

Dollar Spot

Leaf Spots/Melting Out Microdochium Patch Pythium Blight Red Thread Rust Snow Molds

Gray Leaf Spot Pythium Blight Microdochium Patch

Dicarboximides

Diseases Insects

83

Fungicide Mode of Action (MOA) classification Table 3. Mode of action classifications and mobility of fungicides registered for use in turfgrass production1 (Source: FRAC) FRAC2 code

Mode of action (MOA)2

Group

Mobility

Common name

M3 M4 M5 P1 2

Multisite Multisite Multisite Plant defense induction Signal transduction

Dithiocarbamates Phthalimides Chloronitriles Benzothiadiazole (BTH) Dicarboximide

Contact Contact Contact Phloem Mobile Systemic Local Systemic

3

Sterol biosynthesis (Class I)

Demethylation Inhibitor (DMI)

Xylem Mobile Systemic

4 7

RNA polymerase Respiration

Phenylamide Carboximide (SDHI)

Xylem Mobile Systemic Xylem Mobile Systemic

11

Respiration

Strobilurin (QoI)

12 14 19 21 28 33

Signal transduction Lipid peroxidation Chitin synthase Respiration Membrane permeability Unknown

Phenylpyrrole Aromatic hydrocarbon Polyoxin Quinone inside inhibitors (Qil) Carbamate Phosphonate

Xylem Mobile Systemic Xylem Mobile Systemic Xylem Mobile Systemic Local Systemic Local Systemic Local Systemic Contact Local Systemic Local Systemic Xylem Systemic Phloem Systemic

mancozeb captan chlorothalonil acibenzolar-S-methyl iprodione vinclozolin mefentrifluconazole metconazole myclobutanil propiconazole triadimenol/triadimefon triticonazole mefenoxam/metalaxyl fluopyram flutolanil fluxapyroxad isofetamid penthiopyrad azoxystrobin fluoxastrobin mandestrobin pyraclostrobin trifloxystrobin fludioxonil PCNB polyoxin D zinc cyazofamid propamocarb fosetyl-Aluminum (Al) phosphites (Salts of Phosphorus Acid)

43

Delocalization of spectrin-like proteins

Benzamides

Xylem Systemic

fluopicolide

1 These products are labeled for use in turfgrass production.

2 Fungicide Resistance Action Committee (FRAC). Rotate modes of action when possible to minimize the risk of resistance development. For more information on fungicide chemistry and modes of action see www.FRAC.info.

84

Diseases

Fungicides registered for use in turfgrass production Warm-season turfgrass diseases Due to its increased metabolism in high temperatures, warm-season turfgrasses are subject to far fewer major diseases than cool-season turfgrasses. Symptoms mostly occur on warm-season turfgrasses in the fall and spring, particularly in regions where the plant either goes into or comes out of dormancy. Aside from “ultradwarf” varieties used on golf putting greens, the two most important diseases on warm-season turfgrasses are described below.

Large Patch

FOLIAR

Pathogen: Rhizoctonia solani AG2-2 LP Main Hosts: Zoysiagrass, Centipedegrass, Kikuyugrass, Bermudagrass, St. Augustinegrass Description: Large patch occurs when warm-season turfgrass is growing slowly due to low temperatures, particularly in the fall or spring leading into or coming out of winter dormancy.

Most severe disease outbreaks occur in the spring about two to eight weeks after spring green up. Symptoms occur as roughly round patches of tan or straw-colored turf that can range from a few to many feet/meters in diameter, hence the

name “large patch.” When the disease is active, bright orange leaves (also known as “firing” symptoms) are evident along patch margins. The pathogen infects at the leaf sheath, causing a basal rot and reddish brown to black lesions along lower leaf and sheath tissue. Bermudagrass can also be affected by large patch, but the disease is short-lived and recovery occurs more rapidly than in other warm-season species.

Control: Large patch is considerably more severe during periods of heavy rainfall/irrigation and saturated soil conditions. Providing good surface and subsurface drainage will reduce excessive soil wetness and humidity in the turf canopy and thus reduce large patch incidence. Several studies show that large patch severity is not affected or may even be slightly reduced by moderate spring nitrogen applications.

Several fungicides are available for large patch control, but they must be applied preventively and sometimes several times in the fall or early spring to achieve complete control.

Since the pathogen infects lower down on the leaf sheath, applying fungicide in higher water carrier volumes will result in more effective disease control.

Large patch, caused by Rhizoctonia solani AG2-2 LP, results in stand decline of warm-season grasses when plant growth is slowed either going into or coming out of dormancy.

The pathogen infects along the leaf sheath, causing an orange color to leaf blades prior to decline. Patches are light brown to straw colored and can range from a few inches to several feet in diameter. In conducive environmental conditions and disease expansion, patches may “fire” with brilliant yellow to orangish red coloration of infected leaves along the patch margins.

Diseases

85

Table 4. Fungicides registered for Large Patch control in turfgrass production Common name

FRAC Code

azoxystrobin

11

azoxystrobin + acibenzolar-S-methyl azoxystrobin + chlorothalonil

11+P1 11+M5

azoxystrobin + propiconazole

11+3

fluoxastrobin

11

fluoxastrobin + chlorothalonil flutolanil

11+M5 7

fluxapyroxad fluxapyroxad + pyraclostrobin iprodione

7 7+11 2

iprodione + trifloxystrobin

2+11

mefentrifluconazole + pyraclostrobin metconazole myclobutanil PCNB

3+11 3 3 14

penthiopyrad polyoxin D propiconazole

7 19 3

pyraclostrobin

11

pyraclostrobin + triticonazole triadimefon

11+3 3

triticonazole

Trade name Heritage Heritage SC Heritage TL Heritage G Strobe 2L Strobe 50WG Heritage Action Renown Headway Headway G Fame SC Fame G Fame +C Prostar Pedigree Xzemplar Lexicon 26GT Chipco 26019 FLO Iprodione Pro Iprodione SPC Ipro 2SE Ipro 2 Interface Interface Stressgard Navicon Intrinsic Tourney Eagle Turfcide 10G Turfcide 400 Velista Affirm Banner MAXX II Propiconazole Savvi Strider Insignia Insignia SC Pillar G Bayleton 50 Bayleton FLO Trinity

1 Product amounts in fl oz for liquid products and oz for granular products (unless specified).

86

Diseases

Product/ 1,000 sq ft1

Application interval (days)

0.2–0.4 0.8 2 2–4 lb 0.38–0.77 0.2–0.4 0.2–0.4 2.5 4.5 1.5–3 2-4 lb 0.28–0.36 2.3–4.6 lb 3–5.9 2.2 3.25 0.21–0.26 0.34–0.47 4 4 4 4 4 4 4 4 0.7-0.85 0.37 2.4 7.5 lb 16–24 0.7 1 3–4 3–4 3–4 3–4 0.5–0.9 0.4–0.7 3 lb 1–2 1–1.9 1–2

14–28 14-28 14–28 14–28 28 14–28 14–28 14 14–21 14–28 14-28 14–28 14–28 14–28 30 30 14–28 14–28 14–21 14–21 14–21 14–21 14–21 14–21 14–21 14–21 14-28 14 28 21–28 21–28 14–28 7–14 Early Fall 14–28 14–28 14–28 14–28 14–28 14–28 Early fall, early spring Early fall, early spring 14–28