The infection process of Colletotrichum graminicola and relative aggressiveness on four turfgrass species

2003 ◽  
Vol 49 (7) ◽  
pp. 433-442 ◽  
Author(s):  
A Khan ◽  
T Hsiang
Keyword(s):  
Poa Pratensis ◽  
Fungal Growth ◽  
Leaf Tissue ◽  
Creeping Bentgrass ◽  
Infection Process ◽  
Disease Development ◽  
Agrostis Palustris ◽  
Colletotrichum Graminicola ◽  
Annual Bluegrass ◽  
Detached Leaf

Detached 3-week-old leaves of Agrostis palustris, Lolium perenne, Poa annua, and Poa pratensis were inoculated with conidial suspensions of two isolates of Colletotrichum graminicola obtained from A. palustris. Inoculated leaves were incubated at 23 °C under high relative humidity (>95%). The infection process was investigated by light microscopy from 2 to 168 h after inoculation (AI). Spore germination was observed within 2 h AI, appressoria within 6 h AI, and penetration pores within 8 h AI on all four hosts. Infection hyphae were observed inside epidermal cells within 24 h AI on all four hosts, but significantly greater infection was observed in A. palustris and P. annua than in L. perenne or P. pratensis at both 96 and 120 h AI. Acervuli appeared on leaves of A. palustris at 72 h AI and on L. perenne at 96 h AI but were not found on either P. annua or P. pratensis during the first 168 h AI. The infection process was similar to that reported for C. graminicola from other hosts; however, disease development of the two isolates of C. graminicola from A. palustris was faster or fungal growth more extensive on detached leaf tissue of A. palustris than on other turfgrass species tested.Key words: annual bluegrass, anthracnose, creeping bentgrass.

THE INFLUENCE OF WEAR AND NITROGEN ON CREEPING BENTGRASS GROWTH

1983 ◽  
Vol 63 (1) ◽  
pp. 189-193 ◽  
Author(s):  
G. P. KOHLMEIER ◽  
J. L. EGGENS
Keyword(s):  
Sandy Loam ◽  
Leaf Tissue ◽  
Creeping Bentgrass ◽  
Soil Bulk Density ◽  
Root Production ◽  
Reliable Estimate ◽  
Agrostis Palustris ◽  
Leaf Injury ◽  
Annual Bluegrass ◽  
Putting Green

The effects of nitrogen and wear stress on the growth of Penncross creeping bent-grass (Agrostis palustris Huds.) maintained as a putting green was evaluated from June 1978 to November 1979. The 8-yr-old sward was grown on a Fox sandy loam, mowed five times weekly and irrigated as required. Nitrogen was applied as ammonium nitrate at 1.5, 3.0 and 6 kg N∙100 m−2. Wear treatments, applied for specific periods of time, were zero, three and six passes per day. Turf injury was due to direct wear stress rather than soil compaction as the soil bulk density was unaltered by wear treatment. As wear treatments increased, thatch thickness, clipping yields and healing potential decreased. Electrical resistance measurements of leaf tissue decreased as wear stress increased. This technique provided a rapid and reliable estimate of leaf injury from wear stress. Nitrogen at 3 kg∙100 m−2 increased healing potential, turf greenness and root production over the zero N treatment. However, 6 kg N∙100∙m−2 was excessive. Despite the significant increase in green color, there was no significant increase in healing potential and root growth over the 3-kg rate and the annual bluegrass content of the turf was increased.Key words: Annual bluegrass, thatch, healing potential

Susceptibility of Annual Bluegrass and Turfgrasses to Bensulide and Three Uracil Herbicides

Weed Science ◽  
1968 ◽  
Vol 16 (1) ◽  
pp. 16-18 ◽  
Author(s):  
T. J. Neidlinger ◽  
W. R. Furtick ◽  
N. R. Goetze
Keyword(s):  
Root Length ◽  
Poa Pratensis ◽  
Creeping Bentgrass ◽  
Poa Annua ◽  
Agrostis Palustris ◽  
Putting Greens ◽  
Annual Bluegrass ◽  
Golf Putting ◽  
Selective Control ◽  
Length Reduction

Golf putting greens were sprayed with N-(2-mercaptoethyl) benzenesulfonamide S-(O,O-diisopropyl phosphorodithioate) (bensulide). Creeping bentgrass (Agrostis palustris Huds.) and annual bluegrass (Poa annua L.) were observed for injury. Preemergence and postemergence treatments of 5-bromo-3-sec-butyl-6-methyluracil (bromacil), 5-chloro-3-tert-butyl-6-methyluracil (terbacil), and 5-bromo-3-tert-butyl-6-methyluracil (hereinafter referred to as DP 733) were applied to a prepared seedbed planted with Kentucky bluegrasses (Poa pratensis L., var. Merion and var. Newport) and annual bluegrass.Thirty lb/A of bensulide produced leaf discoloration and root length reduction of established annual bluegrass plants without injuring creeping bentgrass. Terbacil at 0.2 lb/A and bromacil at 0.4 lb/A gave highly selective control of annual bluegrass in Merion and Newport Kentucky bluegrasses when applied preemergence to the three grasses. Postemergence applications of these compounds produced moderate selective control of annual bluegrass.

Use of TEM in Plant Disease Diagnosis: A Xylem-Limited Bacterium Associated with Diseased ‘Toronto’ Creeping Bentgrass

1981 ◽  
Vol 39 ◽  
pp. 414-415
Author(s):  
Karen K. Baker ◽  
David L. Roberts
Keyword(s):  
Osmium Tetroxide ◽  
Plant Disease ◽  
Leaf Tissue ◽  
Infectious Agent ◽  
Creeping Bentgrass ◽  
Disease Diagnosis ◽  
Unknown Etiology ◽  
Agrostis Palustris ◽  
Putting Greens ◽  
Plant Disease Diagnosis

Plant disease diagnosis is most often accomplished by examination of symptoms and observation or isolation of causal organisms. Occasionally, diseases of unknown etiology occur and are difficult or impossible to accurately diagnose by the usual means. In 1980, such a disease was observed on Agrostis palustris Huds. c.v. Toronto (creeping bentgrass) putting greens at the Butler National Golf Course in Oak Brook, IL.The wilting symptoms of the disease and the irregular nature of its spread through affected areas suggested that an infectious agent was involved. However, normal isolation procedures did not yield any organism known to infect turf grass. TEM was employed in order to aid in the possible diagnosis of the disease.Crown, root and leaf tissue of both infected and symptomless plants were fixed in cold 5% glutaraldehyde in 0.1 M phosphate buffer, post-fixed in buffered 1% osmium tetroxide, dehydrated in ethanol and embedded in a 1:1 mixture of Spurrs and epon-araldite epoxy resins.

scholarly journals Genetic Variation Among Colletotrichum graminicola Isolates from Four Hosts Using Isozyme Analysis

Plant Disease ◽  
2004 ◽  
Vol 88 (4) ◽  
pp. 402-406 ◽  
Author(s):  
B. J. Horvath ◽  
J. M. Vargas
Keyword(s):  
Genetic Variation ◽  
Genetic Distance ◽  
Geographic Origin ◽  
Creeping Bentgrass ◽  
Genetic Distances ◽  
Colletotrichum Graminicola ◽  
Annual Bluegrass ◽  
Close Relationship ◽  
Host Origin ◽  
Serious Disease

Anthracnose basal rot (ABR) is a serious disease of turfgrasses that is caused by the pathogen Colletotrichum graminicola. The relationships of isolates causing ABR on turfgrasses to those causing disease on important crop hosts (maize, sorghum) remain unresolved. Genetic variation among isolates from annual bluegrass, creeping bentgrass, maize, and sorghum was evaluated based on host origin and geographic origin. Isozymes were used to estimate the genetic variation of the isolates. Five enzyme systems comprising 16 alleles from 5 loci were used. Allele frequencies, genetic distance, and linkage disequilibrium values were calculated for isolates based on both host and geographic origin. Isolates from creeping bentgrass and annual bluegrass were the most closely related based on Nei's genetic distance, while isolates from maize and sorghum were the most distantly related, consistent with their known species-level relationship. Isolates from annual bluegrass and creeping bentgrass had different genetic distances to isolates from both maize and sorghum. Annual bluegrass isolates from different geographic regions had the smallest genetic distance values observed in this study, indicating a very close relationship regardless of geographic origin. Based on these data, it appears that host origin, not geographic origin, plays a more important role in the genetic diversity of these fungi.

scholarly journals Pythium Species Associated with Root Dysfunction of Creeping Bentgrass in Maryland

Plant Disease ◽  
1999 ◽  
Vol 83 (6) ◽  
pp. 516-520 ◽  
Author(s):  
Yan Feng ◽  
Peter H. Dernoeden
Keyword(s):  
Creeping Bentgrass ◽  
Golf Courses ◽  
Agrostis Palustris ◽  
Pythium Species ◽  
Annual Bluegrass ◽  
Large Numbers ◽  
Putting Green ◽  
Pathogenicity Tests ◽  
Cornmeal Agar ◽  
Isolated Species

Putting green samples (n = 109) were inspected for the presence of Pythium oospores in roots of plants from golf courses (n = 39) in Maryland and adjacent states. Twenty-eight Pythium isolates were recovered from creeping bentgrass (Agrostis palustris) (n = 25) and annual bluegrass (Poa annua) (n = 3) plants. Most isolates associated with Pythium-induced root dysfunction were from greens less than 3 years of age and were obtained primarily between March and June, 1995 to 1997. Eight Pythium species (P. aristosporum, P. aphanidermatum, P. catenulatum, P. graminicola, P. torulosum, P. vanterpoolii, P. volutum, and P. ultimum var. ultimum) were isolated from creeping bentgrass and two species (P. graminicola and P. torulosum) were from annual bluegrass. All species, except P. catenulatum, were pathogenic to ‘Crenshaw’ creeping bentgrass seedlings in postemergence pathogenicity tests. P. aristosporum (n = 3) and P. aphanidermatum (n = 1) were highly aggressive at a low (18°C) and a high temperature (28°C). P. graminicola (n = 1) was low to moderately aggressive. P. torulosum (n = 12) was the most frequently isolated species, but most isolates were either nonpathogenic or caused very little disease. P. aristosporum (n = 3) and P. aphanidermatum (n = 1) were highly aggressive and were associated with rapid growth at 18 and 28°C on cornmeal agar. P. volutum (n = 1) was highly aggressive at 18°C, but was one of slowest growing isolates. Infected roots were generally symptomless, and the number of oospores observed in roots was not always a good indicator of disease or of the aggressiveness of an isolate. Large numbers of oospores of low or even nonpathogenic species may cause dysfunction of creeping bentgrass roots.

scholarly journals Cool-season Turfgrass Response to Bispyribac-Sodium

HortScience ◽  
2005 ◽  
Vol 40 (5) ◽  
pp. 1552-1555 ◽  
Author(s):  
Darren W. Lycan ◽  
Stephen E. Hart
Keyword(s):  
Perennial Ryegrass ◽  
Tall Fescue ◽  
Field Experiments ◽  
Poa Pratensis ◽  
Creeping Bentgrass ◽  
Kentucky Bluegrass ◽  
Cool Season ◽  
Severe Stunting ◽  
Annual Bluegrass ◽  
Fine Fescue

Previous research has demonstrated that bispyribac-sodium can selectively control established annual bluegrass (Poa annua L.) in creeping bentgrass (Agrostis stolonifera L.). Annual bluegrass is also a problematic weed in other cool-season turfgrass species. However, the relative tolerance of other cool-season turfgrass species to bispyribac is not known. Field experiments were conducted at Adelphia, N.J., in 2002 and 2003 to gain understanding of the phytotoxic effects that bispyribac may have on kentucky bluegrass (Poa pratensis L.), perennial ryegrass (Lolium perenne L.), tall fescue (Festuca arundinacea (L.) Schreb.), and chewings fine fescue (Festuca rubra L. subsp. commutata Gaud.). Single applications of bispyribac at 37 to 296 g·ha–1 were applied to mature stands of each species on 11 June, 2002 and 10 June, 2003. Visual injury was evaluated and clippings were collected 35 and 70 days after treatment (DAT). Visual injury at 35 DAT increased as bispyribac rate increased. Kentucky bluegrass was least tolerant to bispyribac with up to 28% injury when applied at 296 g·ha–1. Injury on other species did not exceed 20%. Initial injury on perennial ryegrass, tall fescue, and chewings fine fescue was primarily in the form of chlorosis, while kentucky bluegrass exhibited more severe stunting and thinning symptoms. Bispyribac at rates from 74 to 296 g·ha–1 reduced kentucky bluegrass clipping weights by 19% to 35%, respectively, as compared to the untreated control at 35 DAT in 2002. Initial visual injury on perennial ryegrass, tall fescue, and chewings fine fescue dissipated to ≤5% by 70 DAT. However, recovery of kentucky bluegrass was less complete. These studies suggest that bispyribac-sodium has potential to severely injure kentucky bluegrass. Injury on perennial ryegrass, tall fescue, and chewings fine fescue appears to be less severe and persistent; therefore, bispyribac can be used for weed control in these species. Chemical names used: 2,6-bis[(4,6-dimethoxy-2-pyrimidinyl)oxy]benzoic acid (bispyribac-sodium).

Role of Endothall in the Control of Annual Bluegrass in Turf

Weed Science ◽  
1972 ◽  
Vol 20 (6) ◽  
pp. 562-565 ◽  
Author(s):  
A. J. Turgeon ◽  
W. F. Meggitt ◽  
Donald Penner
Keyword(s):  
Poa Pratensis ◽  
Organic Matter Content ◽  
Creeping Bentgrass ◽  
Kentucky Bluegrass ◽  
Matter Content ◽  
Sand Culture ◽  
Annual Bluegrass ◽  
Underlying Soil ◽  
Sand Cultures

Endothall (7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylic acid) was evaluated for controlling annual bluegrass(Poa annuaL.) infestations in Kentucky bluegrass(Poa pratensisL.) and creeping bentgrass(Agrostis stoloniferaL.) turfs. Growth of annual bluegrass was selectively suppressed by three applications of 0.6 kg/ha of endothall, two or three applications of 1.1 and 2.2 kg/ha, and one application of 4.5 kg/ha made to the single plant sand cultures. Field treatments were variable and seasonably dependent. Endothall selectively killed annual bluegrass when applied to roots in sand culture at a concentration of 2.7 × 10−4molar. A granular formulation of endothall provided selective control of annual bluegrass in field and greenhouse studies. High watering frequency prior to application, low organic matter content of the underlying soil, and predominance of the annual biotype of annual bluegrass enhanced the selective action at the lowest rates of endothall application.

scholarly journals Use of the growth regulator paclobutrazol in the management of dollar spot of creeping bentgrass in Minnesota

2005 ◽  
Vol 80 (2) ◽  
pp. 65-70 ◽  
Author(s):  
J. Mercier
Keyword(s):  
Disease Control ◽  
Growth Regulator ◽  
Creeping Bentgrass ◽  
Poa Annua ◽  
Base Line ◽  
Agrostis Palustris ◽  
Dollar Spot ◽  
Annual Bluegrass ◽  
Growing Seasons

The control of dollar spot by paclobutrazol applied as a growth regulator on a creeping bentgrass (Agrostis palustris) and annual bluegrass (Poa annua) fairway turf was compared with two standard fungicide treatments in Minnesota during two growing seasons. Paclobutrazol was applied every 3 weeks, staggered by about 10 days with fungicide treatments (chlorothalonil or propiconazole), also applied every 3 weeks. Paclobutrazol alone significantly reduced the number of dollar spot infection centers during both summers, often by as much as 80%. Chlorothalonil or propiconazole were usually more effective in controlling dollar spot than paclobutrazol. Paclobutrazol improved disease control by fungicides when tested in combination with various rates of chlorothalonil or propiconazole. Paclobutrazol applied as a growth regulator could thus be used to reduce the base line severity of dollar spot of turf.

scholarly journals Tobacco Mosaic Virus Replicase-Auxin/Indole Acetic Acid Protein Interactions: Reprogramming the Auxin Response Pathway To Enhance Virus Infection

2007 ◽  
Vol 82 (5) ◽  
pp. 2477-2485 ◽  
Author(s):  
Meenu S. Padmanabhan ◽  
Sabrina R. Kramer ◽  
Xiao Wang ◽  
James N. Culver
Keyword(s):  
Acetic Acid ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Protein Interactions ◽  
Indole Acetic Acid ◽  
Leaf Tissue ◽  
Infection Process ◽  
Disease Development ◽  
Virus Accumulation ◽  
Cellular Environment

ABSTRACT The replicase protein of Tobacco mosaic virus (TMV) disrupts the localization and stability of interacting auxin/indole acetic acid (Aux/IAA) proteins in Arabidopsis, altering auxin-mediated gene regulation and promoting disease development (M. S. Padmanabhan, S. P. Goregaoker, S. Golem, H. Shiferaw, and J. N. Culver, J. Virol. 79:2549-2558, 2005). In this study, a similar replicase-Aux/IAA interaction affecting disease development was identified in tomato. The ability of the TMV replicase to interact with Aux/IAA proteins from diverse hosts suggests that these interactions contribute to the infection process. To examine the role of this interaction in virus pathogenicity, the replication and spread of a TMV mutant with a reduced ability to interact with specific Aux/IAA proteins were examined. Within young (4- to 6-week-old) leaf tissue, there were no significant differences in the abilities of Aux/IAA-interacting or -noninteracting viruses to replicate and spread. In contrast, in mature (10- to 12-week-old) leaf tissue, the inability to interact with specific Aux/IAA proteins correlated with a significant reduction in virus accumulation. Correspondingly, interacting Aux/IAA levels are significantly higher in older tissue and the overaccumulation of a degradation-resistant Aux/IAA protein reduced virus accumulation in young leaf tissue. Combined, these findings suggest that TMV replicase-Aux/IAA interactions selectively enhance virus pathogenicity in tissues where Aux/IAA proteins accumulate. We speculate that the virus disrupts Aux/IAA functions as a means to reprogram the cellular environment of older cells to one that is more compatible for virus replication and spread.

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