Alabama Turf Times – Dave Han, Ph.D., Auburn University & Alabama Cooperative Extension System
The concept of integrated pest management (IPM) has been around for decades. IPM is taught in colleges and schools across the country, yet it still can be a somewhat mysterious concept. Applying IPM to turfgrass pests can sometimes be very difficult, because maintaining turfgrass often (but not always) is very different from growing a crop for sale. However, the principle of using an integrated program to manage pests can and should be at the forefront of our best management practices for turf. So let’s take a quick look at the concepts behind IPM and how it can work in turfgrass.
What is IPM?
So what is IPM? A great source for a much more in-depth description of IPM is in the Southern IPM Center’s website (https://southernipm.org/about/what-is-ipm/). Their short intro sentence is worth quoting:
“The Integrated Pest Management (IPM) is a sciencebased, sustainable decision-making process that uses information on pest biology, environmental data, and technology to manage pest damage in a way that minimizes both economic costs and risks to people, property, and the environment.”
With that in mind, let’s examine some basic IPM concepts.
IPM uses a variety of tools to manage pests, focusing on the ones the work best with the least negative side effects.
The key aspect of IPM is integration. A true IPM program uses as many different techniques and methods for managing pests as are available, including cultural practices, biologicals and chemical pesticides. The goal is to find which tools manage pests to an acceptable level with the least cost — and here, cost can mean money, environmental impact, health risks to those using the turf, potential liability, or (usually) a combination of all of these. By far, the most important tool in IPM is the mind. IPM is a very active process. It requires a thorough understanding of both the turfgrass and the pests, careful monitoring of the environment, scouting of pest populations, decision-making regarding thresholds of pest populations, and knowledge of many different pest management techniques and when they will or will not help. The best IPM programs are very local in nature: what works at one site may not work at another. Flexibility, the ability to think on the run and, perhaps most of all, common sense are key elements in IPM.
IPM for turf focuses on the grass and how to keep it healthy.
The best possible way to deal with pests is to not have them invade turf in the first place. While this is not always possible, a truly integrated approach to pest management means that every decision made on matters relating to turf care will include consideration of how turf pests will be impacted. How many times have you heard or read that the best defense against this weed or that disease is a healthy turf? That’s because it’s true! But there is a catch.
In the real world, turf managers often must prioritize factors other than grass health.
Everything the turf manager does to the grass should be done in order to maximize turf health and minimize stress. But often this is not the case. We grow grass specifically to stress it and beat it up. For example, sports fields and putting greens are inherently unhealthy places to grow grass because of the stresses of low mowing heights, heavy traffic, compaction, and the pressure to put off maintenance practices that improve turf health to maximize revenue. If we are not careful, the result of unhealthy, stressed grass is a dramatic increase in weed, disease, or insect pest pressure. It can become a death spiral if the turf manager is not always looking ahead and thinking of different ways to mitigate the stress, improve health, anticipate what diseases and weeds could be problems, and start thinking about how to deal with them before they become a disaster.
To be good at IPM, knowledge is key.
If a turf manager doesn’t know their grass inside and out, doesn’t know the environment it’s growing in, and doesn’t know about the possible pests present in the area (both historically and what may be coming along in the future), then they will fail at IPM. IPM places heavy emphasis on knowing about pest life cycles and the various management options available. Knowing about the pest’s biology, and how management options (like pesticides) work allows turf managers to determine the tools they need and the right times to use them to increase turf resistance, disrupt pest life cycles or prevent them from building up to a high enough population to cause problems. This is why any good turf manager keeps up with the latest information available on pest biology, new tools in the kit, and new ways to use existing tools. It can’t be repeated enough: Knowledge is critical to IPM!
Know what pests are where, and how many there are.
Scouting for weeds, diseases and insects is crucial to managing them efficiently. Critical to the effective use of scouting is the concept of setting “action thresholds” for certain pests. This is the point where the population of pests is large enough that action must be taken to prevent unacceptable damage. With weeds and insects, counts can be made in individual plants or bugs. In the case of diseases, it is hard to measure the population of a fungus, so thresholds usually are set based on environmental conditions that favor the development of disease to unacceptable levels. The definition of “acceptable damage” will vary from place to place and sometimes from time to time in the same place. For example, a few weeds may be OK in the fairways on a golf course most of the time, but not the week of a big tournament. Or some disease might be tolerable on a football field in June, but not on a Friday night in September. Setting thresholds for taking action to deal with pests depends on the expectations of the people using the turf, the budget and a host of other factors. It is important to involve as many people as possible in an IPM program, especially when starting out. IPM is not a miracle cure, and there will be some successes and some setbacks. There will be pest damage in some instances, especially in the beginning. Remember that IPM programs are very specific to each site and must be tailored to each set of unique circumstances.
Know the tools available and how best to use them to manage different pests.
IPM wouldn’t be “Integrated” without the use of many different control strategies. These can be broadly divided into the following categories: chemical, biological and cultural. Chemical management strategies are the use of pesticides. As mentioned above, these need to be used in conjunction with effective scouting and knowledge of the pest’s biology to make sure that the treatment is necessary and will be the most effective. Biological management strategies can include a variety of different tools, from the use of EPA-registered biopesticides to compost topdressings and amendments to release of predatory insects and nematodes. Biological tools work better within an IPM plan since most biocontrol agents do not provide complete control of pests. They truly are pest management tools, not pest control ones. They also tend to be slow-acting and are a long-term investment of resources. The goal of IPM, remember, is to provide effective management of pests over a long period of time, not a quick fix. Cultural and physical practices often are adjusted as part of an IPM program. Experimentation with mowing, fertilization, irrigation, aerification and topdressing to find the combination of factors that best reduces pest pressure is important and should never be considered finished. The best turf managers are always tweaking their care routines to improve them. Remember too that cultural practices designed to alleviate one problem many encourage others. Again, there is no substitute for informed experimentation and good communication between all parties involved, so that the best practices can be found quickly.
A general outline for IPM looks something like this:
- Communicate with interested parties about IPM and its goals and determine the management objectives.
For example, on a golf course, greens will have much stricter tolerances for damage than fairways or roughs, and greens would receive priority in scouting effort and in any treatments applied. On a multi-field sports complex, the showpiece stadium field will have priority over outlying or practice fields. Even homeowners often manage front and back lawns to different standards.
- Establish management practices that do not stress turf or favor development of pests, particularly ones known to be a problem in the area.
Mowing at the correct height, maintaining the right soil pH, providing the right amount of fertilizer, not allowing excessive thatch to build up, not allowing soil to compact, and irrigating correctly are vital to keeping turfgrass healthy. Knowing how the pests present in the area react to over-or under-fertilized turf, wet or dry conditions, thatch, and soil problems allows turf managers to know which of these maintenance practices to focus on more closely.
- Scout and record pest levels.
Good record keeping is an essential part of IPM. Since so many decisions must be made based upon data from last season, or several seasons ago, it is wise to make sure records are thorough, accurate and up-to-date. The tools used will vary with the pests being scouted. For insects, visual inspection of above ground turf and of roots is mandatory. Soap flushes, traps, and water floats can help the superintendent to find and count various insect pests. For diseases, visual inspection of foliage and roots is a primary scouting method. So is careful monitoring of the weather. Other scouting methods might include: spectroscopy to detect stressed turf, diagnostic kits, or even a simple field diagnostic laboratory complete with microscopes.
- Take the right action at the right time.
This is where knowledge about pest biology and the management strategies pays off. IPM seeks to find a combination of strategies that minimizes environmental risks but is still effective. Try incorporating some changed management practices or biological methods and use pesticides properly. It is not really the goal of IPM to eliminate pesticide use, but to make sure that pesticides are used as effectively as possible. This definitely means using the right chemical for the job at the right time and rate. It also means trying to use the least toxic chemical available and paying attention to environmentally sensitive areas. It could mean spot-spraying instead of spraying an entire green or fairway. Definitely keep records about any treatment’s effectiveness. Turf managers following IPM are constantly adjusting their treatments according to changing conditions.
IPM is a process, not a cookbook. Although the outlines are easy to make, filling them in takes a lot of knowledge, thinking, communicating and common sense. But the rewards are well worth the effort. Making the most intelligent use of chemicals usually means using less, which saves money and is good for public relations. It is also more effective. Incorporating other management tools into a pest management program also reduces the need for pesticides. IPM is a tool, not a miracle. But it is a very effective tool.READ THE ISSUE