![]() Tony Koski, long-time turf specialist at CSU, for providing many of the pictures used here. Here’s the #1 complaint we’ve been seeing at Tagawa’s.Īnd thanks to Dr. But take heart! Tagawa Gardens is here to help you understand why the problems began, and what to do to help your turf fight back. In short, our lawn’s health is pretty much on us. austalis, but control measures using fungicides have not been reported.Aside from a few types of grubs, most of the problems we see in our lawns are triggered by their environment … the culture, and the care we give them. Fungicide assays have shown significant variation among isolates of L.Avoid applying herbicides or installing new sod during or just before an extended period of hot, humid weather.Avoid low mowing heights and do not mow the grass when it's wet.Do not irrigate turf in the late afternoon or evening.Irrigate thoroughly (deeply) and as infrequently as possibly to avoid moisture stress.Apply adequate amount of complete fertilizers, and aerate compacted soils.Follow accepted turfgrass management practices to prevent severe turfgrass stress.The disease may become severe in turf growing on wet or compacted soil in turf stressed by drought, low mowing, or the activity of other pathogens and in recently transplanted sod. It is usually active on senescing leaves. trifolii is generally regarded as nonpathogenic in turfgrasses, but it can infect and aggressively blights tissues stressed by other pathogens or physiological disorders. However, the disease may appear at any time between spring and autumn. EpidemiologyĮxtended periods of warm, humid weather and stressful soil conditions favor Leptosphaerulina leaf blight. trifolii often is found in association with other turfgrass pathogens, including Pysularia grisea and Phythium spp. The fungus presumably survives adverse period as pseudothecia or as mycelia in plant debris. Leptosphaerulina trifoliiis a common soil saprophyte and unspecialized pathogen that colonizes weakened or senescing tissues of many different plat hosts. No anamorphic (imperfect) state of this fungus has been reported. Asci contain eight ascospores, which are muriform, measure about 25-41 x 10-15 ?m, and have two to six transverse septa and zero to three longitudinal septa. australis McAlpine) produces pale brown pseudothecia, 40-170 ?m in diameter. ![]() Pseudothecia of Leptosphaerulina australis partially embedded in leaf tissue (lateral view)Īscospore of Leptosphaerulina australis Causal Agent ![]() ![]() Pseudothecia of Leptosphaerulina australis partially embedded in leaf tissue (top view) Pseudothecia of Leptosphaerulina australis in blighted leaves of Kentucky bluegrass L eptosphaerulina leaf blight of Kentucky bluegrass on golf fairways Tiny, brown pseudothecia (fruiting bodies) of the pathogen, visible with a hand lens, develop in dead tissues in lesions. The overall effect of the blighting closely resembles bleaching from high-temperature stress, frost, or dull mower injury. Entire leave and sometimes leaf sheaths appear water-soaked and soon turn bleached white or tan. Individual leaves generally die back from the tip and may have yellow, brown, or reddish brown lesions or generalize blighting extending down to the leaf sheath. Large areas of turf may become uniformly blighted, or symptoms may appear in small spots of patches and in localized pockets of more heavily infected grass. Symptoms of the disease may be confused with those of Nigrospora leaf blight, Ascochyta leaf blight, anthracnose, gray leaf spot and dollar spot. The pathogen is saprobic on senescent turfgrass tissues. Leptosphaerulina leaf blight occurs on most turfgrasses, particularly Agrosis, Fetusca, Lolium, and Poa spp. ![]()
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