|
|
|
|
|
Lawn Diseases and Harmfukl Insects
|
|
|
Mowing To Trim Disease The way you mow also affects your lawns ability to resist diseases. · Mow Higher. Most grass should be cut at the highest recommended setting during the summer, to protect the stem from heavy sunlight. The shorter you trim your grass, the smaller the root system will be. · Mow More Often. Mowing higher means doing it more often. Make sure you don't remove more than 1/3 of the grass blade in one mowing. Scalping, or cutting your grass extremely short, leaves it wide open to disease. · Don't Use A Dull Blade Because This Shreds The Tops Of The Grass, And Exposes The Turf's Tissue For Disease Spores To Easily Enter. Mowing with a dull blade is shown to increase disease activity by 20% or more. And it even uses 20% more fuel than mowing with a sharp blade. To avoid this, have your blades sharpened several times a season. · Keep Grass Clippings On Your Lawn, Which Returns About 25% Of The Nutrients Back To The Soil. We want to keep the disease dragons at bay, but we need your help. When we work together, your lawn will stay greener, thicker and more pest free. For more information on disease management, give North American Outdoor Maintenance Outdoor Maintenance a call anytime. Snow Mold: The First Disease of the Year Your lawn was perfect last fall. You spent all summer tenderly caring for it. You faithfully watered it during the hot, dry periods. You mowed at the right height, making sure you never removed more than 1/3 of the grass blade when you cut it. You contracted with a reputable lawn care company to apply the right fertilizers and pest control products to make your lawn healthy and beautiful. You had the best lawn in the neighborhood and were darn proud of it. As fall came, you made sure the leaves were removed as soon as possible, cursing your neighbors who never raked and allowed all their leaves to blow on to your lawn. As the lawn slowed in growth, you gradually lowered the mowing height so it would not mat-down during its winter nap. You even had the lawn core aerated to improve rooting and keep the thatch layer at bay. When the first snows came, you were confident that your lawn was strong enough to survive the tortures of winter. December passed, and then January. The snow came, as it usually does, and turned your lawn white. You were not worried, as you knew you did everything you could possibly have done so that your lawn will be as green and lush in the spring as it was the previous fall. February finally arrives and with it is a mid-winter thaw. Temperatures rise into the 40's, then 50's, and peak at a day with an unseasonable high of 70 degrees. The snow is melting as quickly as water flows off a duck. You look through your window at your grass and are mortified at the sight of your lawn. Turfgrass Disease Diagnostic LaboratoryUniversity of Wisconsin - Madison There are large patches of blighted, straw-colored grass covering half of it. You rush out the door and get down on your hand and knees-not to pray to the mighty lawn god, but to inspect your once beautiful lawn. The grass is a pale yellow color and appears 'glued' together. Your worst fears are confirmed-it is (gasp) Snow Mold! Snow Mold can infect most all types of grasses that must endure a period of freezing temperatures and snow cover. It is often the first disease of the year and may cause your lawn to have an unsightly appearance-especially after the snow melts. Snow Mold can even develop without snow cover. If it is cool, rainy, and overcast, then the disease can become active and affect the lawn. There are two types of Snow Mold. One is Gray Snow Mold or Typhula Blight and the other is Pink Snow Mold or Microdochium Patch. They have similar visual symptoms, but each affects the lawn in a different way. The control of the either disease may require a combination of methods. In severe, reoccurring cases, a combination of chemical, cultural, and biological controls may be required. In less severe cases, a light raking of the affected area may be the best answer. Telling the two diseases apart is simple. Although they both form similar patterns, the main characteristic of Gray Snow Mold is the presence of dark fungus bodies on the blades and crowns of the grass. These fungus bodies, called sclerotia, range in size from pinhead to 3/16 of an inch. Early in the disease cycle, the sclerotia will be yellow to light brown. As the disease progresses, the round-shaped sclerotia will turn dark brown. Visually, Gray Snow Mold begins as spots 1 to 2 inches in diameter and can grow to reach 1 to 2 feet in diameter. Another visual clue to the disease is a halo of grayish-white fungal growth, or mycelium, at the advancing edge of the disease. The infected turf will turn a bleached color and often appears 'glued' together. This is the result of the mycelium drying after it has infected the turf plants. Pink Snow Mold receives its name from the color of the mycelium it produces. It starts being white, but turns a pinkish color as it is exposed to light. Pink Snow Mold forms patterns in the lawn similar to Gray Snow Mold. It is also seen as the snow melts. Both diseases can be active under the snow and can damage large portions of the lawn. Pink Snow Mold is more apt to be active in cloudy, cool, and wet periods and can develop without snow cover. Pink Snow Mold(Courtesy Oregon State University) The control for either of the diseases is easy if the infection is not severe. A light raking of the matted area will loosen the grass and allow the new plants to grow. Be sure to rake lightly, as the ground is usually very wet and the existing grass can be easily raked up. In severe infestation, raking is also recommended, but on a larger scale. It is not advisable to use a power rake as it may also damage the existing grass. Prevention is usually the best answer when dealing with most diseases. This is true for Snow Mold. Follow a balanced fertilization program that provides the necessary nutrients at the appropriate times of year. Thatch management is another important key in Snow Mold prevention. Core aerate the lawn at least once a year to keep thatch levels below 1/2 of an inch. Another important factor is mowing the grass short before winter. Cut the lawn to 11/2 to 2 inches at the last mowing. This should be a gradual process and not a one-time exercise. Lower the height a notch a week until the mower is set at 11/2 to 2 inches. This will prevent the turf from laying over on itself and could increase the chance of Snow Mold. If you do have an outbreak of Snow Mold, it is a good idea to reduce any piles of snow that may remain-especially in shady areas. The longer the snow remains the more moisture and cool temperatures are present. Applying a chemical disease control material to grass already damaged by Snow Mold will do little to change the severity of the disease. Most of the chemical controls should be applied in the late fall as a preventative treatment. Contact your local county extension service for the products that are recommended for your area. Snow Molds are generally not devastating to most lawns, but if left untouched, they can destroy a large part of the lawn. Referring back to the opening scenario of this article, Snow Mold can still develop even if proper care is given to the lawn. A healthy lawn, though, will recover more quickly from the effects of Snow Mold activity. Continue to follow good cultural practices and your lawn will respond and give you the results you want Grubs: Your Lawn's Worst Freeloaders Grubs ? These ugly critters have caused otherwise pleasant people to start personal crusades against this dumb but hungry insect. It doesn't really make sense to get angry at grubs. But it is a good idea to make sure they don't make a meal of your property. What Grubs Do To Your Lawn Grubs feed on the roots of your grass. In areas of extreme damage the turf begins to brown and die, and the sod can be lifted up like a piece of carpet. To check for grubs, simply grab a handful of turf and tug. If grubs are there, chances are the sod will lift off. Grub damage can go unnoticed for weeks and even months on turf that is watered consistently. The grubs stay out of sight under the sod and, with enough water, the turf can appear healthy. But while the damage may not appear quickly, it can completely . devastate a lawn ? making major renovation the only solution. Where Do They Come From? There are many varieties of grubs (also known as white grubs). June beetles (and others) start the cycle by laying eggs in the thatch layer of your lawn. These eggs hatch out as "baby grubs" and begin eating their way through the thatch and into the soil. Grubs feed heavily through late summer and fall until cooler weather sends them deeper into the soil to overwinter. Come spring, they return to the surface to feed until they "pupate" (or go into a type of cocoon) which is when they change into the adult beetles and start the cycle again. When Control Is Needed Grubs are not a concern until there are enough of them to form a damaging population. Healthy lawns can support a wide variety of insects without suffering noticeable damage. Grubs are not "damaging" until we find at least 8 to 10 per square foot. North American Outdoor Maintenance uses several different products to control grubs as either a curative or a preventive treatment. What's important is making sure that the material is active in the soil where the grubs are present but before serious damage occurs. Apply too late (after extensive damage) and you'll get control of the grubs but have a lawn repair job on your hands. If you have any question on this give us call. We'd love to help eliminate freeloading grubs before they make a lunch of your lawn. Sod Webworms Pick The Best Lawns Lawn moths are the flying adults of the sod webworm. If you've got a beautiful, thick lawn, you may get singled out to host a population of these lawn killers. The adults can (and do) fly to the lawns of their choice. They actually pick the better lawns in which to lay their eggs. Sod webworms attack many varieties of grass, but are especially deadly on bluegrass lawns. The early warning of a possible sod webworm problem comes when you see small, brownish-gray moths flying in a jerky, zigzag pattern over the lawn in the early evening. These adults don't damage the lawn, but during these evening flights the moths are laying the eggs that soon hatch into the larvae (or worms) that actually feed on the turf. Damage almost never appears in heavily shaded areas. On the other hand, hot and dry areas are favored by webworms. Webworm Damage Damage first appears as dead patches scattered through the healthy grass. By the middle of the season, large parts of the lawn may be dead. Sod webworm, scattered through the healthy grass are often confused with drought stress to the casual observer. Sod webworms chew the grass blades off very near the thatch layer and drag them into tunnels they build in or above the thatch. The result is patches that look like they've been scalped. Most severe damage shows up in July and August during hot weather. Young Worms Mostly Eat And Sleep Winter is spent as a partially grown larvae several inches deep in the soil. After the first generation of adult moths have laid their eggs, the resulting worms feed for several weeks before going into the resting or pupal stage prior to emerging as new adult moths. There can be 2 and as many as 3 generations of sod webworms per season. A Dirty Job But Someone's Got To Do It The surest way to identify sod webworm damage is to locate the tiny green pellets they leave as excrement. On our hands and knees, we spread the grass between areas of healthy and dead grass (the insects work outward into the healthy grass) to find our evidence. If we locate the pellets, we know the larvae are nearby. The worms themselves are 1/4'' to 3/4'' long, have a segmented body like a caterpillar that is brownish or dusty green. The segments of the body each have several dark spots with two or three stiff, spiny hairs protruding from each of the spots. Remember: · Sod webworm adults are lawn moths that do no damage to the lawn, but lay eggs in the early evening. · The worms (or larvae) do their damage by chewing the grass blades off at the thatch line.
|
|
|
|
|
