Presentation on theme: "LAWN PROBLEMS IN FESCUE LAWNS Prepared by John Johnson Bridgett Hand Camron Jasper."— Presentation transcript:
LAWN PROBLEMS IN FESCUE LAWNS Prepared by John Johnson Bridgett Hand Camron Jasper
Presented by John Johnson Lawn and Garden Manager Ace Peninsula Hardware
THE BIGGEST PROBLEM WITH FESCUE LAWNS IS OWNER OPERATION OF LAWNMOWERS. EITHER THE BLADE IS TOO DULL OR THE GRASS IS CUT TOO SHORT. DULL BLADES TEAR THE GRASS, RATHER THEN CUT IT, LEAVING RAGGED EDGES THAT INVITE ALL KINDS OF DESEASES AND FUNGUI
Toro Lawn Mower Sharp blades help your mower deliver the best quality of cut...but they also contribute to the ongoing vitality of any lawn. That’s because a dull blade... “Mowing with a dull blade shreds the ends of grass leaves, causing browning from tip dieback and a heightened risk of disease. The cleaner the cut, the less the injury.” Dr. Van Cline Toro Agronomist Manager of turf research, Center for Advanced Turf Technology Dull Blades Damage Turf! Shreds plant tips, leaving them vulnerable to attack by fungal disease and increased desiccation Causes the plants to die back, creating an unsightly brown appearance to the lawn Slows the growth of grass blades
Mowing Height and Frequency A neatly trimmed lawn is generally considered to be more attractive than one that is unkempt and shaggy. By mowing frequently and maintaining a uniform turf surface, a neat appearance can be achieved, even at taller heights. Unfortunately, however, a common perception is that a short turf is superior in appearance to tall turf. In reality, turf that is uniform appears neater than uneven turf, regardless of height. Proper height and frequency are the two most important aspects of a turf mowing program. Mowing height Mowing turf at the appropriate height is important to turf health and appearance. Turf cut too short usually has a shallow root system, lacks density, and often requires pesticide applications to stave off weed and pest infestations that commonly occur in stressed lawns. Conversely, tall turf is often considered to be unattractive because of wide leaf blades, low density, and a clumpy, unkempt appearance. In addition, tall turf may not be satisfactory for some sports applications. Mow turfgrasses according to the heights presented in Table 1. Note that a range is listed for each species. When healthy and actively growing, turf can be mowed at the lower heights; raise mowing heights within the desired range during warm-hot periods or when turf is stressed due to drought, disease, shade, insects, or traffic. The heights listed in this table provide a balance between turf appearance and health.
Mowing frequency Turf should be mowed as necessary, not according to a preset schedule. Turfgrasses grow at different rates depending on weather, management, and species. A basic recommendation is to remove no more than one-third of the grass blade at any one mowing. For example, Kentucky bluegrass being maintained at a two-inch height should be mowed when it reaches three inches. This "one-third rule" will help maintain maximum turf root growth. Removing more than one-third of the grass blades may cause root growth to cease while the leaves and shoots are regrowing. This practice can be especially destructive if practiced continuously over a period of successive mowings. Roots may not have a chance to fully develop and the plants will thus be more susceptible to environmental and management stresses. Maintenance of healthy, growing turf root systems should be a primary consideration of any turf management program.
Fescues2 to 3 Turf SpeciesMowing Height (in inches creeping bent grass1/4 to 3/4 Zoysia grass1 to 1.5
Billbugs (crown & thatch inhabitant) Adult billbugs are about 1/5" — 3/4" long. They are beetles with long snouts, or bills, that carry to the tip a pair of strong jaws or mandibles with which the beetles chew their food. Clay yellow to reddish brown to jet black in color. The beetles burrow in the grass stems near the surface of the soil and also feed on the leaves. Several species of billbugs damage lawns. The bluegrass billbug is a bluegrass pest. The Hunting Billbug causes damage to Zoysia grass. Bill Bugs are found in two forms: adult and larvae (infant). The adult Bill Bugs look like a small beetle and are distinguishable by the long elephant-like bill that protrudes from their head. Hence the name. The adult Bill Bug feeds on grass stems above the surface. The younger Bill Bugs, or larvae, look like C- shaped, legless, wet pieces of white-rice and feed on grass roots.
Bill bugs cause the most damage when they are larvae, and can spread and destroy large sections of grass if not contained or killed. Common signs of Bill Bug problems are dead spots on your lawn that don't recover from watering. Since the larvae feeds on the roots, you can also tell by pulling-up on the dead grass and see if it comes up easily from the roots. If so, it could be Bill Bugs.
Chinch Bugs Adapted from the University of Massachusetts
Description: chinch bugs are complex of three different species within the Lygaeidae family. They have piercing-sucking mouthparts and they feed on the sap of grass plants. They reside in the thatch area of the turf grass stand and prefer to feed on the lower leaf sheath and crown area of the plant. The chinch bug can be a major insect pest on home lawns throughout the country. The hairy chinch bug (Blissus hirtus) is the most common species in the Northeast. The hairy chinch bug prefers bent grasses, but will attack many other lawn grasses as well. The adult chinch bugs are about 3 to 5 mm (1/8 to 1/5 inch) in length and black with white markings on the wings. The wings rest flat over the back of the insect and there is a black spot between the wings. Adults may be long-winged or short-winged. There are five nymphal instars of chinch bus ranging in size from 1 to 3 mm (1/32 to 1/5 inch). The first two nymphal instars are red, with a white band across their abdomen, while the third and fourth instars are orange with wing pads just beginning to appear. The fifth instar is black with wing pads easily visible.
Damage: The chinch bug inserts its straw-like mouthparts into the plant tissue and sucks out the plant juices while injecting chemicals into the plant which clog the vascular system. The area around the feeding puncture usually turns yellow. Damaged areas first appear as small, irregular patches which enlarge as the insects spread. Chinch bugs are most damaging in open, sunny areas. Life Cycle: Chinch bugs spend the winter as adults in partially protected areas (under shrubs or around foundations of houses). As the weather warms in the spring, adults move into open areas, where females begin laying eggs. Fifteen to 20 eggs per day are deposited for two to three weeks. The eggs hatch in one to two weeks, and the nymphs begin to suck the juices from host plants. It takes days to reach adulthood. There are two generations per year, with a partial third generation in unusually warm summers. There is considerable overlap of generations, and all stages can be found during the summer.
Detection: Examine the grass in the marginal areas of injured patches, not in the clearly dead grass. Spread the grass gently with your fingers and look in the thatch, near the soil surface. Chinch bugs are usually very active in the summer, so you will be able to see them scurrying around, especially on warm summer days. An alternative method of detecting chinch bugs is to remove both ends of a large tin can, such as a coffee can. Soften the soil a little with water, and insert one end of the can into the ground at least 5 to 8 cm (2-3 inches) deep, leaving at least 10 cm (4 inches) of the can above the ground. Fill the can with water and wait about five minutes. If chinch bugs are present, they will float to the surface of the water, where you can count them. Control: In many instances, chemical control of chinch bugs is not necessary. Studies in Michigan have demonstrated that lawns which receive adequate amounts of water throughout the summer (preferably weekly deep watering) are able to tolerate relatively high populations of chinch bugs without sustaining damage. In addition, many lawns have natural populations of predators, such as ground beetles or "big-eyed bugs," which can keep chinch bug populations from getting out of hand.
Insecticide applications sometimes have very adverse effects on these predators, causing the chinch bug populations to develop more rapidly in subsequent years. Plant resistance has also been reported for a number of turf grass species and cultivars. Research has demonstrated strong resistance of endophyte-enhanced turf grasses to the hairy chinch bug. Turf grass managers usually control chinch bug populations after major damage has occurred. To avoid this problem in areas with habitual problems, an April to mid-May insecticide application will control the overwintering females and subsequent generations during the summer. Reinfestation may occur from adjacent areas, but this process is slow and may require an additional year or more. This adult treatment must be made before egg laying occurs. As with any pesticide application, be sure to read the label and apply the material at the specified rate. Avoid mowing the area for two or three days afterward. Adapted from the University of Massachusetts Extension, 1999
Grubs University of Illinois
White Grubs in Lawns Concerns are often raised about white grubs in lawns and ways to manage them. Late summer into early fall is the time white grub problems are most likely to show in lawns here in northern Illinois. While a relatively small percentage of lawns will actually get white grubs in a given year, this insect can cause serious damage when a significant population occurs on a lawn or other turf area. Since white grubs are often asked about, this month’s Lawn FAQ features white grubs in lawns and summarizes the most common questions regarding this pest of home lawns. How do I know if I have grubs in my lawn? Why does my lawn have grubs but not my neighbor? How can I predict if my lawn will have grub damage this year? Can I prevent grub damage? What about using organic controls for grub control? What should be done after grub damage has occurred?
How do I know if I have grubs in my lawn? White grubs feed on the roots of grasses, so lawns will show wilting and browning of irregular shaped areas. Certainly there could be many reasons for lawns browning, especially in late summer when most grub damage occurs. Always check the root zone of affected areas for the white, c-shaped grubs. Carefully pull back the sod in suspect areas, in particular the marginal areas where brown grass meets green grass, and look for the grubs. Usually a population of about 10 or more grubs per square foot will lead to browning of the lawn. Peeling back a damaged lawn area has revealed these white grubs in the soil as the cause.
Keep in mind other factors that can lead to poor rooting and are mistaken for grubs. For example, lawns in shade areas often have weak roots and are pulled-up easily. Grubs do not typically appear in shade lawns. Also, many lawns were easily pulled up this spring and grubs were blamed. Once grass dies, regardless of the cause, roots will rot away and the grass is very easy to tear out. So trying to diagnose grub damage from the previous season as the cause of a dead lawn area in spring is very difficult to do, even if limited roots are found in an area of dead grass. Raccoons and skunks have damaged this lawn area looking for grubs. Another sign of grubs is damage from skunks and raccoons digging up lawns in search of grubs to eat. This usually happens at night. Moles may or may not be feeding on grubs so are not a reliable indicator of grub problems.
Why does my lawn have grubs but not my neighbor? Keep in mind the adult stage of the grub life cycle is a beetle, which can fly. Random chance is part of the answer. But adult beetles usually lay eggs in full-sun lawn areas with adequate soil moisture. The masked chafer (annual white grub) and Japanese beetle lay eggs in July. So if the weather has been dry but your lawn is watered and surrounded by dry lawns, it is a prime target for egg laying How can I predict if my lawn will have grub damage this year? It is difficult, as insects can go in cycles and many factors influence the chances of grubs appearing in your lawn. Lots of adult beetles on the lawn in July is one indication. Masked chafers, the adult of the annual white grub, are tan beetles active shortly after sundown. Japanese beetles fly during the day and feed heavily on many ornamentals. Noting these adults and then having irrigated lawns surrounded by drier turf increases the chances of grub damage to your lawn. Watch lawns closely starting about mid-August and continuing into September for wilting and browning areas, and then check the root zone for grubs.
The masked chafer is the adult beetle which lays eggs becoming the annual white grub in lawns Japanese beetles, which have been increasing in Illinois, feed on many plants as adults and lay eggs in lawn areas which may become a grub problem later in the season
Can I prevent grub damage? There are some options to consider. One option is allowing the lawn to go into dormancy if conditions dry due to lack of rainfall in July, reducing the odds of grub damage since the adult beetles look for green lawns with good soil moisture for egg laying. The downside is the lawn will be brown and dormant. Also, this may not be reliable if rainfall keeps grasses green throughout July, although if all lawns are green, the chances of significant grub damage on any one lawn are low since the adult beetles tend to disperse and lay eggs over a much broader area under this scenario. Another option is to closely monitor the lawn as we advance into late summer and be ready to act if grubs start to appear. Watch for grass areas going off-color and just starting to brown, in particular those areas that have been irrigated. Check the root zone for small white grubs. Insecticides such as diazinon or trichlorfon (Dylox) can be applied when grubs are first noticed to prevent large-scale damage. Other insecticides such as imidacloprid (Merit) or halofenozide (GrubEx) can be applied prior to noting damage, such as in late July to lawns likely to show damage (adult beetles present, irrigating lawn). All of these insecticides should be watered into the soil for best results. Lawns should also be watered prior to application. With all insecticides, read and follow label directions. To confirm what a product contains as active ingredient, check the active ingredient section on the front of the label
What about using organic controls for grub control? Heterorhabditis bacteriophora nematodes have shown good results for white grub control. Nematodes are very small unsegmented worms. This particular species will search out white grubs and after entering the grub, release bacteria that kills the grub. This product is available in mail order catalogs, often sold as Hb nematodes. This product should be applied late in the day to lawns with adequate soil moisture and then watered in immediately. What should be done after grub damage has occurred? If significant grub damage has occurred, the lawn will need some renovation work in early fall. Rake away dead debris. Water the lawn area, as some of the grass with damaged roots may recover, especially if the weather cools down. Bare or thin areas may need some reseeding. Labor Day is a good target date for lawn renovation work in northern Illinois.
Brown Patch / Large Brown Patch Rhizoctania solani Brown Patch, which is also known as large patch, is a common soil-borne fungus that attacks a variety of plants including almost all turf grasses. It is most common to Bermuda, Kentucky Bluegrass, Centipede Grass, Bent grass, St. Augustine, and ryegrasses in regions with high humidity and/or shade. Tall fescue is also prone to the development of Brown Patch. Brown patch commonly starts as a small spot that can quickly enlarge. As the disease progresses and becomes larger, it will take on a circular, or sometimes a horseshoe shape, that could be several feet across or larger. As the infected area becomes larger, the initially infected area begins to recover, creating a brown circular pattern in the lawn. Conditions most favorable for brown patch development include the presence of active fungi responsible for the disease coinciding with a seasonal time when the susceptible grass is aggressively growing combined with a climate where daytime temperatures range between 75 — 85 degrees and night-time temperatures hover above 65. Poor surface and subsurface drainage combined with excessive fertilization (nitrogen) are both factors that greatly increase the intensity of this disease.
Brown Patch Symptoms On warm season turf grasses, the disease is characterized by at least two different types of symptoms. The most common is a circular pattern of brown grass with a yellowish ring (smoke ring) of wilted grass on the perimeter of the diseased area. The leaves can be easily pulled from the stolons with the smoke ring because the fungus destroys the tissue at the base of the leaf. Symptoms first appear as small circular patches of water-soaked, dark grass that soon wilt and turn light brown. Stolons often remain green as the disease develops, the circular patches enlarge, smoke-rings become apparent and new green leaves may emerge in the center of the circular areas. Control When environmental conditions are favorable, brown patch is likely to develop on susceptible turf grasses. The severity of the disease can be somewhat controlled by following a strict fertilization schedule that only apply the proper amount of nitrogen and trace elements during the ideal times; by watering early in the morning to remove dew and all the grass to dry quickly; mow grass a little taller with a sharp mower blade, and when possible, by bagging the lawn
clippings during likely periods of disease activity. Fungicide applications are most effective when used as a preventative before the disease has become established in the lawn. Since brown patch typically only kills the leaf, lawns attacked by brown patch will usually return when conditions improve as long as secondary problems do not take advantage of the turf grass in its weakened state. Prevention The best prevention for brown patch is to aerate often, reduce shade to effected areas, and follow a fertilization schedule to help prevent fertilization with excess amounts of nitrogen. Avoid irrigating late in the day. Do not over-fertilize. Treatment The most common fungicides used on Brown Patch are: benomyl, and chlorothalonil. The brown patch fungus will survive in thatch and turf debris between periods of activity. Chemical controls are available, but should only be applied by licensed applicators. Contact your local lawn care provider for additional information.
Dollar spot is rare on sports turf and professional landscapes. Outbreaks may occur in residential lawn turf and can reduce the lawn ’ s aesthetic quality and contribute to an overall decline in turf vigor. Dollar spot is one of the most readily identifiable diseases on golf course turf. Characteristic symptoms on creeping bent grass include small (up to 1 inch in diameter), round, tan-colored spots (Figure 1). The spots often occur in clusters and can cause considerable damage to playing surfaces if not appropriately managed (Figure 2). Figure 3 shows a research site where various treatments were applied to control dollar spot (green rectangles). The brown turf surrounding the treated areas shows severe dollar spot damage. In the early morning hours after a long dew period, the dollar spot pathogen will produce an abundance of mycelia on affected plant parts (Figures 4, 5). Characteristic symptoms on individual plants include distinct lesions on leaf blades (Figure 6) with straw-colored centers and red-brown margins. Leaf spot symptoms are more readily observed on taller mown turf species such as Kentucky bluegrass and perennial ryegrass. The dollar spot pathogen survives in the turf environment as mycelium in infested turf debris. The pathogen becomes active with rising temperatures in the spring. Mycelial growth and infection occur during extended
dew periods (longer than 8 hours) over a broad range of temperatures (55˚-80˚F). On golf course fairways and putting greens, dollar spot severity is increased significantly in nitrogen-deficient turf. On residential turf, dollar spot usually accompanies the normal depletion of nitrogen nutrition in late spring or early Summer. The pathogen produces no spores; spread occurs through radial growth from individual infection centers and by the movement of infected and infested leaf blades, usually through turf maintenance operations such as mowing and core aeration. Dollar spot is caused by a fungal pathogen (Sclerotinia homoeocarpa) that blights leaf tissues but does not affect turf grass roots or crowns. The disease is a common concern on golf course turf, especially creeping bent grass and annual bluegrass greens, tees, and fairways, where it can result in poor turf quality and appearance.
Leaf Spot North Carolina State University
SYMPTOMS Leaf spot and melting out are common diseases in bluegrasses and bermuda grasses caused by species of Drechslera and Bipolaris (formerly known as Helminthosporium). In the bluegrasses, this disease is most active during warm and humid weather, but in bermudagrasses, most damage occurs during cool and wet periods in the fall and spring. Leaf spot symptoms are expressed in the early stages of the disease, but if left uncontrolled, the pathogen may progress into the basal portions of the plant to cause “melting out”. Leaf spot symptoms initially appear as small, brown or black spots or flecks on the leaves or sheaths. As the lesions expand, the center of the lesions becomes tan with a dark brown or black border. The lesions may also be surrounded by a yellow halo. As the lesions expand, they coalesce and cause dieback of entire leaves or plants. Melting out symptoms appear as a reddish brown rotting of the sheaths, crowns, rhizomes, or stolons which initially leads to wilting, yellowing, or death of the foliage. Symptoms of leaf spot and melting out appear in irregular patterns, although localized “hot spots” may be more severely damaged than others.
FACTORS AFFECTING DISEASE DEVELOPMENT Leaf spot/melting out is one of several Helminthosporium diseases which survive in thatch during periods that are unfavorable for disease development. These fungi are most active during periods of cool (60 to 65 degrees F) and wet weather, but some are able to cause disease whenever temperatures are above freezing. Leaf spot/melting out is most severe on turf that is growing slowly due to adverse weather conditions or improper management practices. Shaded areas with little or no air movement result in weak turf and extended periods of leaf wetness that favor disease development. Deficient or excessive nitrogen, excessive thatch, extended periods of leaf wetness, drought stress, and low mowing heights are factors that encourage the development of Helminthosporium diseases. These fungi may spread to the crowns and roots and cause melting out, which is most severe during periods of hot weather.
CULTURAL CONTROL Use turfgrass cultivars with resistance to this disease when available. Planting resistant cultivars is one of the most effective and economical ways to manage leaf spot and melting out. Refer to the results of cultivar evaluation trials operated by the National Turfgrass Evaluation Program or local Universities for cultivars with leaf spot resistance that perform well in your area. If planting cool-season turf, use blends and mixtures of multiple species and/or varieties when possible.. Fertilize to meet the nutritional needs of the turf but avoid over-stimulation and the development of lush, succulent growth. Do not apply more than one pound of nitrogen per 1,000 square feet in a single application. Mowing heights and frequencies should be within the recommended range for the turfgrass species being managed. Keep the mower blades sharp to prevent open wounds through which the fungus can enter. Reduce extended periods of leaf wetness by watering deeply but infrequently to wet the entire root zone. Use the Turf Irrigation Management System available on Turf Files to schedule irrigation based on weather conditions and turf needs. Do not irrigate just before or after sunrise, and ensure good surface and soil drainage. Remove unwanted vegetation that impedes air movement and prune trees to allow for light penetration. Power rake or dethatch to remove excessive thatch and reduce the potential for pathogen survival. Regular aerification and topdressing of golf greens is also necessary to reduce thatch buildup.Turf Irrigation Management System
CHEMICAL CONTROL Leaf spot can be controlled on a preventative or curative basis. However, applications are most effective when made in the early stages of development. Once the disease reaches the melting out stage, fungicides may not cure infected plants but will help to reduce further spread of the disease. Susceptible turfs should be monitored frequently for signs of disease activity during periods of cool and wet weather.