Talking Herbicides (Part 1)

Question: What’s the most important thing golf course superintendents need to keep in mind when forming a weed control program?

When establishing a weed control program, it’s crucial to properly identify the weeds you’re trying to control. No matter where in the country you’re located, knowing the difference between crabgrass and bahiagrass, for example, is critical to selecting the right herbicide. Herbicides, like medications, are designed to treat specific weeds. Look at it this way, you wouldn’t treat a stomachache with a product that’s meant for a headache. It’s important to remember there isn’t a magic bullet when it comes to weed control. It takes research and education. Take advantage of university professionals, local extension services and online information. Know what you’re up against when making that weed control decision, and read the product labels so you aren’t wasting time and money.

Jason Fausey | Weed Scientist, Nufarm

A sound weed control program starts with knowing both the herbicide program that has been in place and the results previously achieved. Document what have been the most troublesome weeds and seem to be escaping your current weed control program, as well as the timing the breakthrough is occurring. You can then focus both on product choice and application timing for your new program with more accuracy. No herbicide controls every weed, and often you will have greater success by focusing on chemistries that control the target problem weed(s). Application timing of the proper herbicide is also critical to the long-term success of a program, as well as ensuring all the correct cultural practices such as watering, mowing, use of an adjuvant and tank mixture recommendations are followed. Labels are a great source of information as well as manufacture literature on the best practices for each product.

Owen Towne | President, Phoenix/UPI

An effective weed control program encompasses several factors. Some key issues are target weeds (annual/perennial; pre-emerge versus postemerge), timing (fall, spring, split applications), historical problems and escapes, potential weed-resistance
issues, phytotoxicity to desired turf species and budget. Generally, split applications applied in the fall and spring provide the most complete control. This is especially true for annual and perennial grasses. There are numerous products available for this, including brands containing prodiamine, oryzalin, pendimethalin, oxadiazon, dithiopyr and others. Broadleaf weeds are controlled economically by a multitude of postemergent products, usually containing one or more of the following: 2,4-D, MCPP, MCPA, dicamba, MSMA, sulfentrazone, quinclorac and others.

Colleen Tocci | Marketing Manager,
Engage Agro USA

Be proactive and form a weed control program that includes herbicides, but also investigate alternatives — such as the integration of biological, mechanical and traditional removal practices — to minimize the chance of weed resistance to a product. Using the same herbicide(s) or products with the same active ingredient can lead to resistance. When selecting herbicides, try products with different modes and target sites of action and implement a rotation of those products. In addition, tank mixing a combination of herbicides aimed at controlling the same weed spectrum and modifying the application timing/rates can also be effective.

Dave Loecke | Herbicide Product Manager,
PBI-Gordon Corp.

Healthy turf is your best defense against weeds, and selecting the right product for the job is critical. It’s important to know and understand your target weeds, and equally important to understand the herbicide technology and application timing for optimum results. Different weeds are better controlled at different times of year and growth stages. You need to understand both the weed you’re fighting and the tools you have to fight it.

Michael Prudhomme| Consultant/Specialty
Business, SipcamAdvan

Timing! Other aspects are important, but if you miss the timing, you’re not going to achieve the objective, nor will you get a good return on your investment. Failing to achieve the original objective usually leads to additional unplanned applications and costs, and with some weeds you don’t get a second chance. With pre-emergent herbicides it’s critical to apply and get activation from moisture prior to weed germination. It’s also important not to apply too far ahead of germination so that the residual control plays out prematurely. With postemergent herbicides, application timing for the correct weed size is absolutely critical for control. Herbicide labels are good about defining maximum weed size controlled, as well as the duration and application timing for pre-emergent products. Pay attention to herbicide rate ranges, which can provide additional flexibility for your timing.

Kyle Miller | Senior Market Development
Specialist, BASF

I have two recommendations you should keep in mind when forming a weed control program. Know what weed control solutions are available and schedule herbicide applications. In the last five years, several new herbicides have been introduced into the market. It’s critical for you to stay abreast on the latest technologies to understand what’s available for which weeds. Secondly, don’t wait until you have a weed problem to figure out what needs to be done. Make sure to schedule your herbicide applications in advance. Knowing what weeds have occurred in the past allows you to apply preventive applications versus curative applications.

Laurence Mudge | Manager,
Green Solutions Team, Bayer

Proper weed identification is critical in forming a weed control program. Modern turf herbicides aren’t necessarily broad-spectrum and may not control the problematic weeds on your course. Weeds aren’t susceptible to all herbicides. Many herbicides are effective on grassy weeds, but may not be that effective on broadleaf weeds, and the reverse is also true. In addition, annual weeds tend to be easier to control than perennial weeds, and this impacts what the weed control should be. We recommend a broad-spectrum, pre- and postemergent herbicide program for optimal control of problem weeds.

Dean Mosdell | Western Field Technical Manager, Syngenta

Correct identification of weeds is essential for effective weed control. Are you trying to control annuals or perennials? What is their life cycle? You also need to assess why you have weeds. Oftentimes, environmental imbalances can prevent a dense turf canopy, which is the best defense against weeds. Several factors can cause thinning turf, such as poor drainage, fertilization levels, mowing height, soil compaction or shade. To control weeds, an agronomic program with appropriate cultural practices and strategic herbicide selection will help you create healthy turf without overreliance on herbicides, which can lead to resistance.