Pest Management for Turf
By Janet S. Hartin
Excerpted from Become and Landscape Company Owner' by Janet Hartin (fabjob.com)
Doing whatever it takes to keep turf healthy is by far the best protection against diseases, insects and weeds. Watering, fertilizing, and mowing correctly, as well as keeping the soil well drained and thatch levels down prevents at least 80% of turf diseases. Stressed grass is much more prone to outbreaks than healthy grass.
There is always potential for disease and pathogens are almost always present in the turf environment. The key to remember is that infection won’t occur without the right environment (temperature, water, light, etc.). That’s why taking good care of the grass is your best bet to avoid diseases. It all starts with planting the right grass. Make sure you choose one that not only grows well in your climate but also is going to be able to stand up to intended use. Some, just by their nature, take more wear and tear. And, it’s important to identify the potential disease before you try to control it, especially if you’re thinking about spraying it with a pesticide. Some common diseases make the grass look bad for a few weeks but don’t cause any long-term problems once the weather sides with the grass again. And, spraying a fungicide on what turns out to be a watering or insect problem doesn’t 1q cure the problem and actually hurts the turf by killing off the ‘good guy’ microorganisms. Few, if any, fungicide applications should be necessary if you choose your grass right and take good care of it.
Identify the Problem. It’s important to find out what’s wrong with the grass as soon as you can. This means staying on top of things and walking the site often enough (usually once a week) to catch anything right away. The longer a problem goes, the worse it often becomes. And, once the grass is hit with one thing, it becomes weak and more likely to contract something else. In that way, plants are a lot like you and me. When we have a cold, even though it’s tempting to ignore it and just keep going full speed ahead, it usually backfires and we’re down longer than had we taken care of ourselves.
Damage that looks like it’s from a disease is often caused by incorrect watering. In fact, this is the most common mistake made. Brown spots from uneven watering account for lots of confusion. That’s where those ‘can tests’ and walk throughs come in that we talked about earlier. Other causes may be uneven fertilizing, scalping from mowing too low, lawn chemicals or insects. Or, it could be a problem due to the weather. Maybe it’s hotter or colder than normal.
Turf Diseases
If you do have a lawn disease, it’s probably caused by a fungus. You might see spots on the leaves, or yellow or thin grass, rotted roots, or small or large circles with a ‘frog eye’ (healthy grass in the center of dead grass). For help identifying diseases, submit a sample (as described below) to a reputable lab. It may also be useful to look at pictures on sites such as the University of Florida turfgrass disease site http://edis.ifas.ufl.edu/LH045,
North Carolina State University http://www.ces.ncsu.edu/depts/ent/ppil/lab.html or
University of California http://www.ipm.ucdavis.edu/PMG/selectnewpest.turfgrass.html for photographs and descriptions of several common lawn diseases. Chapter 3 lists Cooperative Extension contacts for each state. Most have specific information on turf and lawn diseases.
Sampling for a Turf Disease. When you’re pretty sure there’s a disease outbreak, it’s a good idea to get a professional involved. In this case, you’ll want help from a plant pathologist, a scientist who studies plant diseases. You don’t need to always have a specialist visit the site (which can be expensive and wastes valuable time if no one can come out right away) each time. You can take your own sample and send it to a reputable lab. Learning how to take a good sample is important since an accurate diagnosis depends on it. Do this as early in the game as possible. Contact your local Cooperative Extension or Agricultural Commissioner office for a list of diagnostic laboratories.
Insects. Insects are usually not a serious problem on turf, especially when the right grass is chosen and is well cared for. This means watering, fertilizing, dethatching, mowing, and aerating correctly. Grass that is healthy stands up better to insect attack than stressed grass. All that said, your clients may still may get some insect damage. It usually shows up as small, scattered patches of yellow or brown lawn. Diseases, lawn chemicals and even dog urine can look very similar so make sure you know what you’re looking at. If you do see a bug or two, don’t overreact. Many insects you’ll uncover are ‘good guys’ and are winning the war against the ‘bad guys’.
Common beneficial insects include predatory ants, ground beetles, and ladybird beetles. That’s why spraying before you find out what’s actually causing the problem isn’t a good idea. And, even one or two ‘bad’ insects don’t usually need to be killed with an arsenal of chemicals, especially if you don’t see any turf damage. Many don’t do much harm in small numbers; only one or two per square yard aren’t going to hurt the grass as much as you might end up hurting it by wiping out predators.
Know what levels of specific insects are acceptable before you spray. There are some great sites online that discuss what these levels are. They vary by area, so check your local Cooperative Extension publication website listed in Chapter 3. If you find a species of insect in levels greater than their threshold, you should think about trying a non-chemical product such as Bacillus thuringiensis or beneficial nematodes (the good guys!) before jumping right into a chemical control. If you do decide to use a chemical insecticide, follow the label directions carefully.
Insects that may cause damage include root and leaf-feeding caterpillars such as white grubs ( the larvae of beetles), masked chafers, billbugs, and chinch bugs. Each insect leaves its own clue to its identify. Some of these culprits can be seen just by looking at the grass with the naked eye or with a 10X hand lens. Other are smaller, nocturnal, or just trickier and you need to outsmart them in order to even find them.
Plant-parasitic nematodes. These are not the same ‘good guys’ sometimes used for insect control. While both are tiny roundworms, 1/50 to 1/16 inch (0.4 - 1.5 mm) long, the ones that injure turf feed on the plant, whereas the beneficial nematodes don’t. In Florida and California, root-knot nematodes can damage and even kill turf. Nematodes attack all species of grass and leave patches of yellow, wilted plants. Irrigating, fertilizing and aerating correctly can prevent damage. Root knot nematodes cause galls to form on roots that can lead to disease outbreaks. Sodded lawns growing in sandy soils can have major nematode problems. The only way to really know if your client has a nematode problem is to send a soil/root sample to a reputable lab. Try to prevent nematodes from becoming a problem; it’s almost impossible to get rid of a bad case. Prevention is key.
Weeds. The best and easiest way to prevent a huge weed problem in your client’s lawn is to avoid them altogether. They’ll take over thin areas pretty quickly, so make sure the grass is healthy and thick and establish a new lawn quickly. This will not only keep weed seeds from germinating, but helps the grass out-compete any weeds that do sneak in. Remember that weeds produce thousands of seeds, so prevention is key. Following recommended irrigation, fertilization, mowing and aeration practices will really help the grass stay ahead of the game.
With all this said, you’ll probably still get a weed or two. Know what it is. In most cases, hand weeding or light hoeing is all you’ll need to do if you’re maintaining a client’s lawn. Larger plantings with more serious problems may require chemical control. Get to know some reliable licensed pest control advisors/applicators that you respect and trust. Recommend their services to your customers or consider getting a state license yourself.
