• 식물병연구
• /
• 제16권1호
• /
• pp.94-96
• /
• 2010

In May of 2004 through 2007, Leptosphaerulina leaf blight caused by Leptosphaerulina trifolii occurred on Kentucky bluegrass (Poa pratensis) at golf courses in Gangwon Province, Korea. Symptoms on the turfgrass caused by L. trifolii were leaf blights, dying from the leaf tip downwards to the crown, which appeared patches in the field because of local pockets of severely infected (blighted) grass. Perithecia were produced on old or weak leaves, including club-shaped asci, each of which contained 8 pale brown muriform ascospores with cross and longitudinal septa. Ascospores of the fungus isolated from the diseased leaf tissue and cultured on potato-dextrose agar (PDA) were muriform multicellular (composed of 3-6 cells) and $23.4-40.5{\times}7.8-15.6{\mu}m$ in size with 3-4 transverse and 0-3 longitudinal septa, which were morphologically identical to L. trifolii reported previously. DNA sequences of ribosomal RNA gene (internal transcribed spacer) of the fungus were homologous with similarity of 99% to those of L. trifolii isolates in GenBank database, confirming the identity of the causal agent of the disease. Pathogenicity of the fungus was also confirmed on the creeping bentgrass by Koch's postulates. This is first report of Leptosphaerulina leaf blight on turfgrass caused by L. trifolii in Korea.

• 한국식물병리학회지
• /
• 제10권1호
• /
• pp.54-60
• /
• 1994

Incidence of Rhizoctonia blight ranged from 22.2% to 100% in the golf courses at six geographical locations in Korea from 1989 to 1993. Rhizoctonia blight occurred more severly in southern area than in northern area. Fifty seven isolates of Rhizoctonia solani obtained from diseased parts of zoysiagrasses were grouped to AG2-2 by anastomosis test. Pathogenicity testes revealed that this pathogen was strongly pathogenic to Korean lawngrasses(Zoysia japonica, Z. matrella, Z. tenuifolia), but not pathogenic to creeping bentgrass(Agrostis palustris), bermuldagrass(Cynodon dactylon), Kentucky bluegrass(Poa pratensis), perennial ryegrass(Lolium prenne), and creeping red fescue(Festuca rubra subsp. rubra L.). The isolation frequency of R. solani AG2-2 fro sheaths of the infected plants was the highest by 91.67%, and that from stolons and roots was 11.13% and 5.63% respectively. The pathogen was not isolated from the leaves. Population density of R. solani in the lawn of large circular patch was highest on surface soils down to 1 cm deep with the value of 4.9$\times$104 (CFU/g soil), but below 1 cm population density decreased sharply down to 0.8~9.8$\times$103 (CFU/g soil). Horizontal distribution of propagules in turfgrass soil was higher in the margin than in center of patch, where the number of propagules was similar to these of healthy looking soils close to the margin of diseased patch. The meteorological factors influencing the outbreak of the disease were temperature, the number of rainy days and precipitation. Optimum temperature for disease development of Rhizoctonia blight in field was 20~22$^{\circ}C$, and that for hyphal growth of R. solani AG2-2 in vitro was 25~3$0^{\circ}C$. In Pusan area, Rhizoctonia blight first occurred in late April and rapidly developed in late June. The disease slightly decreased during July to August and developed again in late September in 1993. The monthly disease progress in Pusan area was similar to that in Kyeonggi province.

• 한국잔디학회:학술대회논문집
• /
• 한국잔디학회 2002년도 제15차 한국잔디학회 정기총회 및 춘계학술발표회
• /
• pp.3-5
• /
• 2002

This study was carried out to get better understandings about morphological, ecological, and genetical characteristics of annual bluegrass collected from different golf courses in Korea and eventually to establish a successful control strategy. Twenty five local lines of annual bluegrass collected from 20 golf courses in Korea were classified into annual or perennial type on the basis of morphological characteristics. Twelve local lines showing obvious morphological differences were selected and then genetically assessed using RAPD analysis. Classification of the 12 local lines through RAPD analysis were considerably similar to that determined by both of morphological differences and phenotype. Responses of the two types of annual blugrass to herbicides were also examined. Shoot growth of annual bluegrass was significantly suppressed by flazasulfuron and the annual type was more susceptible than perennial type, regardless of flazasulfuron concentrations used. By pendimethalin treatment, there was no clear difference in susceptibility between the two types of annual bluegrass. However, by the treatment of dithiopyr, annual type was more sensitive than perennial type in both shoot and root growth. Nine tree species were screened to detect their allelopathic potential on turfgrasses and annual bluegrass. Acacia (Robinia pseudo-acacia) leaves showed selective inhibition in the shoot and root growth as well as their seed germination when treated with 2% and 10%(v/v) of the extract. However, the other leaf extracts except acacia inhibited non-selectively the growth of three turfgrass species such as bentgrass, perennial ryegrass and zoysiagrass and annual bluegrass. The PAL activities of annual bluegrass increased at 24 h after treatment of acacia leaf extract and peaked at 36 h and then decreased till 60h. The highest PAL activity was observed at 36h after treatment of 10%. The highest activity of CA4H in annual bluegrass was observed at 2h after treatment of acacia extract and the level was 4 times greater than that of the control. The phenolic acids such as p-coumaric acid, salicylic acid and ferulic acid were increased with the treatment of acacia leaf extract. The chloroplast membrane and cell wall of annual bluegrass were destroyed by treatment of acacia leaf extract and its inner materials were released. The membranes in annual bluegrass cells might be destroyed by phytotoxic compounds from acacia leaf extract.

• 한국응용곤충학회지
• /
• 제41권3호
• /
• pp.217-223
• /
• 2002

주둥무늬차색풍뎅이는 성충이 각종 활엽수의 잎을 가해하여 피해를 주는 해충이지만 유충에 의한 피해도 벤트그라스에서 기록되어 있다. 그러나 진주골프장의 퍼레니얼라이그라스에서 7월에 잔디가 황화 현상을 보이면서 시들음 증상이 나타나 조사한 결과, 주둥무의차색풍뎅이 유충에 의한 피해로 확인되었다. 피해는 한지형 잔디의 하고현상과 비슷하나 관수 후에도 잔디의 활력이 회복되지 않고, 부분적으로 고사가 일어나는 차이를 보였다. 한편, 주둥무의차색풍뎅이 유충의 환경친화적 방제를 위하여 한국산 곤충병원성 선충의 효과를 실험실과 골프장에서 수행하였다. 실험실내에서 주둥무의차색풍뎅이 3령충은 Heterorhabditis bacteriophora 제주 strain과 Hererorhabditis sp. 경산 strain, Steinernema carpocapsae 포천 strain, S.glaseri 동래 strain, S.longicaudum 논산 strain 중 H.bacteriophora 제주 strain과 Heterorhubditis sp. 경산 strain에 의한 치사율이 95%로 가장 높았다. 골프장 fairway에서의 야외실험에서는 H. bacreriophora제주 strain과 Heterorhabditis sp. 경산 strain, S.carpocapsae 포천 strain에 의한 유충 감소율이 28-57%로 다양하였다.