Since perennial ryegrass can sustain serious damage in a short period of time, preventative fungicide applications are recommended for gray leaf spot control. Gray leaf spot on perennial ryegrass is a widespread problem in the Midwest, especially on golf course fairways and athletic fields during periods of warm humid weather with frequent rainfall or irrigation. This photo from a reader is one of the worst examples I’ve ever seen. Symptoms first appear on lower leaves about two to three weeks before tasseling. Lush leaf tissue produced by turf that is fertilized with excessive nitrogen is extremely prone to infection by the gray leaf spot pathogen. Buffalo grass is the most common species in Australia to be affected by this disease. Gray leaf spot is a foliar disease that affects perennial ryegrass and tall fescue. Gray leaf spot disease can be managed by watering early in the morning, limiting use of … Learn More About NC State Extension, We have several topic based e-mail newsletters that are sent out periodically when we have new information to share. In Harvey . N.C. Gray Leaf Spot (fungus – Pyricularia grisea). Perennial ryegrass is most rapidly affected by the disease, with widespread turf loss occurring in a period of a few days. Gray leaf spot lesions on corn leaves hinder photosynthetic activity, reducing carbohydrates allocated towards grain fill. Most of the time in Australia, Gray Leaf Spot is a minor disease of turf. Host Grass: St. Augustine Grass(Stenatophrum secundatum). North Carolina citizens each year through local centers in the state's 100 counties When climatic conditions are humid and warm for prolonged periods the disease can develop to the extent that loss of turf cover can occur. Grey Leaf Spot first appears as tiny, brown leaf and stem lesions, which enlarge rapidly into round to oblong spots. Perennial ryegrass cultivars with resistance to gray leaf spot are starting to become available. Gray Leaf Spot on Corn. Gray leaf spot is a generally a summer disease. Gray leaf spot (GLS) is a foliar fungal disease that affects grasses. Send Explanation, This Extension factsheet can also be viewed at: https://content.ces.ncsu.edu/gray-leaf-spot-in-turf. The largest spots may extend nearly across the entire leaf and become a bluish-grey in colour. If conditions favor disease development, economic losses can occur. NC State Extension is the largest outreach program at NC State University. Update in September 2018 – Because of the cool and very wet weather pattern we’ve seen over the last few weeks, there’s been a tremendous increase in reports of Brown Patch and Gray Leaf Spot in our area. The gray coloration in the center of the lesions is a flush of spores produced after incubation at 100% relative humidity for 24 hr. Tomato gray leaf spot control is actually quite simple provided you practice good cultivation and hygienic routines. Collect clippings when gray leaf spot is active to reduce further spread of the disease. Lawns with severe gray leaf spot have areas that seem to just fade or melt away. Where will you find Gray Leaf Spot? In the USA ryegrass is very susceptible to Grey Leaf Spot, but in Australia to date this hasn’t been a major problem for this grass. It is especially troublesome in shaded areas that remain damp for some time. This grass must be mowed frequently during the summer months to remove excess leaf tissue, keep the canopy open and dry, and remove developing gray leaf spot lesions. Reports of this problem from studies done in Ohio indicate that blight found on hakone grass is caused by the same fungus that causes gray leaf spot on perennial ryegrass and fescue. In grasses other than maize it is caused by Pyricularia grisea, which only infects perennial ryegrass, tall fescue, and St. Augustinegrass in places with warm and rainy climates such as Florida. Find out about symptoms and management. In this section you will find case stories and expert advice specific to the golf industry. Gray leaf spot initially appears as spots on the leaves that are round or oval, tan in color, and have a dark brown border. Gray leaf spot of corn. Cooperative Extension, which staffs local offices in all 100 counties and with the Eastern Band of Cherokee Indians. New hot spots of the disease have been reported in the Mohawk Valley and the Leatherstocking Region. Most of the time in Australia, Gray Leaf Spot is a minor disease of turf. It is more likely to develop in regions which experience high humidity levels and temperatures of 26-32 C. What damage or effects will Gray Leaf Spot have? Figure 1. Newly sprigged, sodded, or rapidly growing grass is more susceptible than well-established grass. How to Prevent and Treat Gray Leaf Spot in Houston. Gray leaf spot may develop when temperatures are between 70 and 95°F, but the fungus also requires at least 14 hours of continuous leaf wetness in order to initiate infection. Brown specks scattered through the leaf surface is a characteristic symptom of gray leaf spot. The leaves of tall fescue and perennial ryegrass blighted by gray leaf spot are typically matted and greasy in appearance. In St. Augustinegrass, gray leaf spot is most active from June through August. The symptoms of Leaf Spot vary depending upon what caused the fungus to emerge on the plant. The fungus causing gray leaf spot overwinters in and on corn debris left above and on the soil surface. These are blown by wind onto the lower leaves of the present season's corn plants. Can I reapply Daconil for grey spot and how much time should I wait in between applications? The disease was of primary concern for those growing perennial ryegrasses but incidence and severity on tall fescue has been increasing. Gray leaf spot may develop when temperatures are between 70 and 95°F, but the fungus also requires at least 14 hours of continuous leaf wetness in order to initiate infection. Infection by the GLS fungus damages the plant by reducing the amount of healthy leaf area capable of producing the energy needed to grow/maintain the plant and make grain. We have the fungicides you need to prevent those issues.. Gray leaf spot is a foliar disease which can infect leaves and stems of susceptible turf varieties. Closer inspection of … Host range of the fungus is more than 50 grass species, including wheat, crabgrass, and foxtail. Is Propiconazole 14.3 the most effective fungicide to treat gray leaf spot on St. Augustine? It is caused by a fungal pathogen (Pyricularia grisea) that readily infects and kills leaf blades. Gray leaf spot on tomatoes is a classic example and is one of the many diseases that can strike plants in the nightshade family. Funding for this site is provided by the Center for Turfgrass Environmental Research and Education, the Turfgrass Council of North Carolina and the College of Agriculture and Life Sciences at North Carolina State University. Viewed from afar, the affected turf shows irregular sweeps/washes of light green/yellowing grass among normal areas. On St. Augustinegrass, grey leaf spot first appears as small, brown spots on the leaves and stems. Leaf infections can progress into the crown area, resulting in death of individual plants. Gray leaf spot does not develop in distinct patches in St. Augustinegrass, but affected leaves may wither and die, causing a brown cast to the turf that is visible from a distance. Gray leaf spot, caused by the fungus Cercospora zeae maydis is the most significant yield-limiting disease of corn worldwide [1].The disease was first reported in Illinois in 1924, and has increased in prevalence throughout corn growing regions since 1988. Will Eagle 20EW Specialty Fungicide treat gray leaf spot on St. Augustine? . Chrysanthemum white rust is a disease of plants caused by... We would like to use cookies to better understand your use of this website. Leaf spot symptoms of gray leaf spot are shown on a St. Augustinegrass leaf blade. The spots quickly enlarge to approximately 0.5 cm in length and become bluish-grey in colour and oval or elongated in shape. Based in the College of Agriculture and Life Sciences, we reach millions of Managing leaf wetness is an effective means for minimizing gray leaf spot in all hosts. Gray leaf spot can have a substantial impact on yield under favorable conditions. Gray Leaf Spot – Corn 6-15 1 Gray Leaf Spot – Corn Gray leaf spot (GLS) is a foliar disease of corn caused by the fungus Cercospora zeae-maydis. In time, the leaf spots expand and girdle the leaf, causing it to die back from the tip. As every veteran corn producer knows, corn is susceptible to a myriad of foliar fungal diseases. When does Gray Leaf Spot occur? Like the leaf spots, these patches rapidly coalesce to produce large, irregular areas of damaged turf. Subscribe By Email chevron_right. Although Leaf Spots can be caused by air pollutants, insects, and bacteria among other factors, most of the time it is due to an infection by pathogenic fungi. As the disease develops the spots have grey coloured centres surrounded by a brown margin. Usually, the initial infections occur in mid-June to late June but the disease does not begin to spread rapidly until late July and August. Proper mowing, fertilization, and irrigation practices will reduce the chances of significant turf loss from this disease. Fungicide resistance to the Qol fungicides (Compass, Fame, Heritage and Insignia) has been documented in gray leaf spot, therefore it is necessary to rotate through multiple chemical classes when managing this disease including the use of tank-mixtures. Gray leaf spot is a devastating disease of cool-season turfgrasses such as perennial ryegrass and tall fescue. The symptoms of grey leaf spot vary depending on the grass cultivar. The disease is typically most severe in the first year of establishment, but then gradually becomes less damaging as the turf matures. Do not apply nitrogen to susceptible grasses in late spring or summer. Years of fungicide application research demonstrate that the single best time to apply a fungicide to corn for gray leaf spot … . A preventative program should be initiated in mid-June or early-July in most locations, with repeat applications on a 14 to 21-day interval. We also have a few other mailing lists you can subscribe to. Treating gray leaf spot in new lawns is a problem in Houston because of the need to water the new grass and the high humidity we have in the Gulf Coast Region. The earlier the infection occurs, the more time there is for secondary spread and leaf d… In tall fescue and perennial ryegrass, foliar blighting initially occurs in patches from 4 to 12 inches in diameter that are orange to yellow in color. Cooperative Extension has offices in every county, https://content.ces.ncsu.edu/gray-leaf-spot-in-turf, Mountain Horticultural Crops Research & Extension Center, Vernon G. James Research & Extension Center, Entomology – Insect Biology and Management, Mountain Horticultural Crops Research and Extension Center, Weed Management in Nurseries, Landscapes & Christmas Trees, azoxystrobin + acibenzolar-S-methyl (Heritage Action)*, azoxystrobin + difenoconazole (Briskway)*, chlorothalonil + acibenzolar-S-methyl (Daconil Action)*, chlorothalonil + iprodione + thiophanate-methyl + tebuconazole (Enclave)*, chlorothalonil + propiconazole (Concert)*, chlorothalonil + propiconazole + fludioxonil (Instrata)*, fluopyram + trifloxystrobin (Exteris Stressgard), flutolanil + thiophanate-methyl (SysStar), mefentrifluconazole + pyraclostrobin (Navicon)*, propiconazole (Banner MAXX, Propiconazole), pyraclostrobin + fluxapyroxad (Lexicon Intrinsic), tall fescue, perennial ryegrass, and St. Augustinegrass. N.C. necrotic spots can also merge causing collapse of large areas of the leaf tissue. Gray leaf spot initially appears as spots on the leaves that are round or oval, tan in color, and have a dark brown border. Proper mowing practices are most important for gray leaf spot management in St. Augustinegrass. Any factor that increases the amount of leaf wetness will increase gray leaf spot development such as extended periods of cloud cover, improper irrigation timing / frequency, or extended rainfall events. Gray leaf spot is caused by the fungus Cercospora zeae-maydis. The relationship between the amount of leaf tissue affected by gray leaf spot and the amount of yield loss is unclear. This Extension factsheet can also be viewed at: You will automatically get notified when we post news to this site. Gray leaf spot is a turf disease that affects St. Augustinegrass primarily during Forida’s rainy, humid summers. Schedule irrigation early in the morning, before sunrise, and never in the late afternoon or evening. Gray Leaf Spot: Robbing Corn Yields. Gray Leaf Spot | Turf Disease | How to eliminate Gray Leaf Spot Turf Disease. Leaf spot is a fungal disease but can also be caused by bacteria. Want to see which lists are available? Gray leaf spot (GLS) is a common fungal disease in the United States caused by the pathogen Cercospora zeae-maydis in corn. Because of this symptom, gray leaf spot is often confused with Pythium blight in tall fescue and perennial ryegrass. In tall fescue and perennial ryegrass, most cases of the disease appear from late July through September. Rapidly expanding lesions will sometimes have an olive green, water-soaked border. Cultivars of tall fescue and St. Augustinegrass vary considerably in gray leaf spot susceptibility. Information available on this site is provided by faculty and staff in the Departments of Crop and Soil Sciences, Entomology and Plant Pathology, and Horticultural Science at NC State University. Symptoms start as small dark spot which enlarge as the disease develops. Gray Leaf Spot Outbreak. benzovindiflupyr + difenoconazole (Ascernity)*, pydiflumetofen + azoxystrobin + propiconazole (Posterity XT)*, What made it so helpful? Read our Commitment to Diversity | Read our Privacy Statement. Brown to reddish-brown lesions and streaks may be associated with some fescues and ryegrasses. Mow to recommended heights, using the “1⁄3 rule” as a guide for mowing frequency. Photo credit: General symptoms of Gray Leaf spot infection (Photo: Roger Clark, AGS) The first known UK case of Gray Leaf Spot disease on perennial ryegrass turf signals the arrival in Britain of potentially the most damaging fungal disease for this grass variety – and it’s a problem that can be extremely difficult to control Apply nitrogen and other nutrients as recommended to maintain vigorous foliar growth during the summer months.