The disease is most often associated with kentucky bluegrass poa pratensis. Magnaporthe grisea, also known as rice blast fungus, rice rotten neck, rice seedling blight, blast of rice, oval leaf spot of graminea, pitting disease, ryegrass blast, and johnson spot, is a plantpathogenic fungus that causes a serious disease affecting rice. If you have kentucky bluegrass, fescue or annual bluegrass, and youre noticing some unsightly rings of dead grass, theres a chance you might have something called summer patch. First report of magnaporthe poae, cause of summer patch. The genome of magnaporthiopsis poae was sequenced by the broad institute. Summer patch summer patch affects kentucky bluegrass and annual bluegrass on all kinds of turf venues, including golf courses, athletic fields, professional landscapes, and residential lawns. The ectotrophic, rootinfecting fungus magnaporthe poae is the cause of summer patch of kentucky bluegrass poa pratensis. Summer patch of kentucky bluegrass caused by magnaporthe poae. Lawn fungus symptoms and appearance home guides sf gate. Magnaporthales contains important pathogens of cereals and grasses, e. First report of magnaporthe poae, cause of summer patch disease. Magnaporthe poae introduction kentucky bluegrass poa pratensis, annual bluegrass poa annua, and fescues festucasp. The disease first appears in the warm weather of the summer, typically after rainy periods or heavy downpours. Summer patch appears as circular yellow or tan areas up to 1 foot in diameter, consisting of dead and dying plants.
Summer patch is caused by the fungus magnaporthe poae. It causes grasses to form light green patches up to 24 inches wide that later turn a reddishbrown. Symptoms of summer patch normally develop in late june through august and reappear in the same location year after year. Kentucky bluegrass annual bluegrass creeping bentgrass. It produces darkcolored hyphae fungal strands that can damage and kill roots. Another problematic disease this summer was summer patch magnaporthe poae which happens predominantly on kentucky bluegrass and commonly occurs when temperatures are above 82. Summer patch is one of the most destructive diseases of kentucky bluegrass. Summer patch, magnaporthe poae, and necrotic ring spot, leptosphaeria korrae, are two separate diseases which attack turfgrass roots and previously were referred to as fusarium blight. The primary cause of summer patch is a type of fungus called the magnaporthe poae. Summer patch is caused by a soilborne pathogen that begins infecting turfgrass roots, crowns and rhizomes when midspring temperatures reach 65 degrees f.
Summer patch is caused by a fungus, magnaporthe poae, which lives in the soil and attacks the roots. Magnaporthiopsis poae kentucky bluegrass fungus, synonym magnaporthe poae, causes summer patch of poa species, creeping bentgrass, and fineleaved fescues. From summer patch, penn state center for turfgrass. A close picture of brown patch lesions on turfgrass leaves. Managing patch disease in lawns lawn talk university of. Fungus fescues brown patch large patch or rhizoctonia blight rhizoctonia solani. Department of agriculture usda prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and.
Summer patch is a lawn disease that occurs during warm weather and attacks lawns all across the united states. Kentucky bluegrass poa pratensis, annual bluegrass poa annua, and fescues festuca sp. Lawn disease quick reference wisconsin horticulture. Summer patch magnaporthe poae small tan or strawcolored spots appear on the leaves in early summer. Magnaporthe poae causes summer patch, which leaves circles of yellow throughout your lawn. Fungal diseases of lawns missouri botanical garden. Foliar symptoms of summer patch are most commonly observed during high summer temperatures after a previous spring infection period. It can decimate kentucky bluegrass lawns and athletic fields and annual bluegrass putting greens. Cultivars of perennial ryegrass and tall fescue differ in their resistance to the summer patch fungus. Magnaporthiopsis poae are known as ectotrophic rootinfecting fungi, indicating superficial growth and colonization of these pathogens along the. Summer patch is a rootdestroying fungus, which helps to differentiate this lawn disease from diseases that it imitates, such as dollar spot and necrotic ring spot. Lack of moisture in the soil or improper irrigation is the likely cause. First report of summer patch of kentucky bluegrass caused.
Vascular discoloration and cortical rot occur in later stages of the disease. Affected areas may appear dark green initially and then reddishbrown to bronze colored. Summer patch, magnaporthe poae northeastern ipm center. Characteristic symptoms of the disease are rings of affected turf that start with a reddish brown discoloration and then turn tan or light straw color.
It is considered one of the most important diseases on turfgrass in north america. We now know that necrotic ring spot caused by the fungus ophiosphaerella korrae and summer patch caused by the fungus magnaporthe poae are two distinct root rot diseases that can develop in the same turf area. Fungus fescues fusarium patch microdochium patch or pink snow mold microdochium nivale. The anamorph was isolated from poa pratensis and poa annua roots in the course of an investigation into the aetiology of summer patch disease of turf grasses. The center of the tan discolored patch usually remains green giving rise to the alternate name, frogeye patch. In order to allow comparative analyses with other fungi, a copy of this genome was imported into mycocosm. Management and control of summer patch magnaporthe poae, page 3. A frequent bane of warmer climate regions, summer patch is caused by the lawn fungus magnaporthe poae and is often associated with shallow root systems due to poor soil conditions. Summer patch caused by magnaporthe poae is a highly destructive disease of poa species and fineleaved fescues. Kentucky bluegrass, annual bluegrass, fine fescues. Summer patch is a lawn disease that is active during the summer when turfgrass roots are growing very slowly. The proper name for this lawn disease is magnaporthe poae, and it generally affects lawns from june into september. Another view of dark hyphae, typically produced by the summer patch fungus. A recently published 6gene phylogeny see figure below with selected taxa in the magnaporthaceae indicates that the current concept of both magnaporthe and gaeumannomyces are polyphyletic.
Summer patch of bluegrasses umass center for agriculture. Ectotrophic root infecting eri fungi are one of the most destructive classes of turfgrass diseases. Early stages of the disease may be difficult to detect. Prior to the mid 1980s, summer patch and necrotic ring spot were part of an unexplained disease complex called fusarium blight. For more information, see our necrotic ring spot and summer patch of turfgrass fact sheet. This rootdestroying fungus is recognizable by the 1 to 2 circular patches of dead grass it causes to appear on the lawns it infects. Confirm the presence of summer patch before you treat. This reddish color is an early symptom of something more severe and often only appears after a small area of grass has died. The fungus that causes summer patch, magnaporthe poae, is a pathogen of the roots of bluegrasses and fine fescues.
Diseases of lawns and turf statewide ipm program uc anr. Magnaporthe oryzae, the takeall pathogen of cereals gaeumannomyces graminis, and the summer patch pathogen of turfgrass magnaporthiopsis poae. In mowed turfgrasses kentucky bluegrass and annual bluegrass summer patch attacks roots and crowns and shows up as dead patches. Summer patch is a turfgrass disease caused by the fungus magnaporthe poae. Young roots may appear healthy, although dark brown hyphae may be present on these tissues. The disease was first described in 1984 by smiley and cravenfowler. Summer patch disease symptoms evident now horticulture. Summer patch magnaporthe poae or necrotic ring spot ophiosphaerella korrae while arguably not as prolific as some of the other diseases listed so far, summer patch and necrotic ring spot in kentucky bluegrass can be one of the more difficult diseases to manage. Magnaporthe salvinii is the type species of magnaporthe. This publication discusses how to identify the fungi, its characteristics and how to. Summer patch is very dangerous for kentucky bluegrass, annual bluegrass and creeping red fescue lawns. Symptoms occur later in the summer during high temperatures.
Magnaporthales is an order in sordariomycetes of ascomycota with about 200 species. Initially, summer patch resembles dollar spot but patches quickly grow and affect large areas of turf. Magnaporthe poae causes summer patch of poa species, creeping bentgrass, and fineleaved fescues. Summer patch is the common name for patches of brown or yellow grass caused by the magnaporthe poae fungus. Some patches may have circles of green grass in the center, sometimes called frog eyes. The causal agent of summer patch, the soilborne fungus, magnaporthe poae, infects the plant. Red fescues are generally considered resistant to these diseases. Research continues to look for information on these diseases. The disease occurs mostly on kentucky bluegrass poa pratensis, fescues festuca sp. The soil borne fungus magnaporthe poae which causes summer patch colonizes grass roots and crowns in may and early june.
Summer patch and necrotic ring spot are common fungi that affect turfgrass. The fungus is commonly found in the soil and does not really attack the grass until the appearance of some external factors, one of which is the hot weather. The fungus rhizoctonia cerealis causes yellow patch, which leaves smaller circles of yellow. Summer patch of turfgrasses horticulture and home pest news. This disease is active only during the warmest part of the summer. If you manage your turf properly, it can recover quickly from brown patch. Summer patch on turfgrass magnaporthe poae introduction. Symptoms are present during the months of may through september, and include dead circles and arches of turf that range. These spots enlarge and coalesce until large areas of the lawn are killed. The disease is widely distributed in the midatlantic region of the united states and west to central nebraska and kansas 2. Bentgrassagrostis palustris, fescue, poa seriespoa sp.
Symptoms of summer patch disease on kentucky bluegrass lawn. Summer patch can sometimes exhibit similar symptoms to necrotic ring spot, which makes correct identification a crucial. I ol cornell university college of agriculture and life. Magnaporthe poae nc state cals nc state university. More likely on turf stressed by heavy traffic, poor air circulation and. Magnaporthe poae summer patch on turfgrass bugwoodwiki. Management and control of summer patch magnaporthe poae. Rings of dead grass are typical symptoms of patch disease. Summer patch leaves 6 to 12inch circle patches of deadlooking grass throughout a lawn. The normally weak pathogenic, soilborne fungus magnaporthe poae with a phialophora state causes summer patch disease when hot, sunny days.
The summer patch pathogen, magnaporthe poae, is active during late spring and summer when turfgrass root growth is diminished. Fungicide applications can be done in the spring but need to be started before the fungus enters the roots when the average soil temperature at 3 inches depth is between 6070 degrees f. This pathogenic fungus, one of the important root pathogens of turfgrass, attacks and colonizes susceptible turfgrass roots suffering from environmental or cultural. Saturated soils have been shown to exacerbate disease development.
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