Lesson #4 - Perennial Weeds of High
Soil Moisture Continue to be an Issue Another takeaway from last year was that perennial weeds that prefer moist soils continue to be problematic. Weeds such as Kyllinga (Kyllinga spp.), yellow nutsedge (Cyperus esculentus), purple nutsedge (Cyperus rotundus), Virginia buttonweed (Diodia virginiana), and doveweed (Murdannia nudiflora) continue to infest warm- and cool-season turfgrasses across Tennessee and beyond. As a result, many of the newest herbicides entering the turfgrass marketplace have been developed with these weeds in mind including (but not limited to) Aethon, Celero, Dismiss NXT, GameOn, Relzar, SwitchBlade, and SurePower. Regardless of product, controlling these perennial weeds will likely require sequential applications in addition to improving the growing environment to favor turfgrass growth in lieu of weeds.
Te 2018 season served as yet another reminder that weed control programs work very well and that there are many different ways to customize a program for a given sod farm. Te proactive process of developing a weed control program offers key advantages including:
• Weeds are exposed to different herbicidal modes of action, either in rotation or mixtures with one another; doing so will therefore reduce selection pressure for resistant biotypes.
• Programs allow sod producers to always improve their effectiveness in controlling weeds. Te best turfgrass managers in our industry take notes throughout the season about weed management strategies that were (or were not) effective and can build programs based on this information. Tis process is very different than simply approaching the problem “the way it’s always been done” or making choices about weed management based on what herbicide is the most discounted in an early order program.
• Programs can be tailored to a specific field or subset of fields at a given farm. For example, different programs can be implemented on different fields to account for variations in growing environment—which makes a great deal of sense considering that no two fields are the same.
Yellow nutsedge (Cyperus esculentus) infesting a tall fescue (Festuca arun- dinacea) turf.
Lesson #5 - Programmatic Thinking
Works For the past several years our team has encouraged turfgrass managers to implement weed control programs at their facilities, similar to what is done when managing turfgrass diseases. What is a weed control program? It is simply a well thought out strategy to maintain turfgrass as weed-free as possible from January through December. Weed control programs can incorporate different herbicide applications along with timely cultural practices to deliver an integrated approach to weed control. Tis proactive strategy is very different from the reactionary approach many take to controlling turfgrass weeds—i.e. seeing an infestation and spraying the most readily available herbicide.
36
Jim Brosnan, PhD, is associate professor in the Plant Sciences Department of the University of Tennessee (UT) – Knoxville and director of the UT Weed Diagnostics Center. Greg Breeden, MS, is a weed science extension assistant responsible for managing all turfgrass weed science field trials at UT. José J. Vargas, MS, is a research associate responsible for managing all turfgrass weed science greenhouse and laboratory research projects at UT, particularly those focused on herbicide resistance mechanisms in weeds. Jose currently serves as the head diagnostician at the UT Weed Diagnostics Center.
All photos by Dr. Jim Brosnan.
For more information on turfgrass weed control, please visit the University turfgrass weed science website that serves your state, county, country and/or geographic region. Te University of Tennessee’s turfgrass weed science website is
tnturfgrassweeds.org but there probably will be other resources available to you locally. Additionally, practitioners are encouraged to visit mobileweedmanual. com, a tool developed by University of Tennessee Extension professionals to assist green industry professionals in selecting herbicides for use in turf and ornamentals.
TPI Turf News May/June 2019
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76
