TY - JOUR
T1 - A temperature and leaf wetness duration-based model for prediction of gray leaf spot of perennial ryegrass turf
AU - Uddin, W.
AU - Serlemitsos, K.
AU - Viji, G.
N1 - Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2003/3/1
Y1 - 2003/3/1
N2 - Gray leaf spot is a serious disease of perennial ryegrass (Lolium perenne), causing severe epidemics in golf course fairways. The effects of temperature and leaf wetness duration on the development of gray leaf spot of perennial ryegrass turf were evaluated in controlled environment chambers. Six-week-old Legacy II ryegrass plants were inoculated with an aqueous conidial suspension of Pyricularia grisea (approximately 8 × 104 conidia per ml of water) and subjected to four different temperatures (20, 24, 28, and 32°C) and 12 leaf wetness durations (3 to 36 h at 3-h intervals). Three days after inoculation, gray leaf spot developed on plants at all temperatures and leaf wetness durations. Disease incidence (percent leaf blades symptomatic) and severity (index 0 to 10; 0 = leaf blades asymptomatic, 10 = >90% leaf area necrotic) were assessed 7 days after inoculation. There were significant effects (α = 0.0001) of temperature and leaf wetness duration on disease incidence and severity, and there were significant interactions (α = 0.0001) between them. Among the four temperatures tested, 28°C was most favorable to gray leaf spot development. Disease incidence and severity increased with increased leaf wetness duration at all temperatures. A shorter leaf wetness duration was required for disease development under warmer temperatures. Analysis of variance with orthogonal polynomial contrasts and regression analyses were used to determine the functional relationships among temperature and leaf wetness duration and gray leaf spot incidence and severity. Significant effects were included in a regression model that described the relationship. The polynomial model included linear, quadratic, and cubic terms for temperature and leaf wetness duration effects. The adjusted coefficients of determination for the fitted model for disease incidence and severity were 0.84 and 0.87, respectively. The predictive model may be used as part of an integrated gray leaf spot forecasting system for perennial ryegrass turf.
AB - Gray leaf spot is a serious disease of perennial ryegrass (Lolium perenne), causing severe epidemics in golf course fairways. The effects of temperature and leaf wetness duration on the development of gray leaf spot of perennial ryegrass turf were evaluated in controlled environment chambers. Six-week-old Legacy II ryegrass plants were inoculated with an aqueous conidial suspension of Pyricularia grisea (approximately 8 × 104 conidia per ml of water) and subjected to four different temperatures (20, 24, 28, and 32°C) and 12 leaf wetness durations (3 to 36 h at 3-h intervals). Three days after inoculation, gray leaf spot developed on plants at all temperatures and leaf wetness durations. Disease incidence (percent leaf blades symptomatic) and severity (index 0 to 10; 0 = leaf blades asymptomatic, 10 = >90% leaf area necrotic) were assessed 7 days after inoculation. There were significant effects (α = 0.0001) of temperature and leaf wetness duration on disease incidence and severity, and there were significant interactions (α = 0.0001) between them. Among the four temperatures tested, 28°C was most favorable to gray leaf spot development. Disease incidence and severity increased with increased leaf wetness duration at all temperatures. A shorter leaf wetness duration was required for disease development under warmer temperatures. Analysis of variance with orthogonal polynomial contrasts and regression analyses were used to determine the functional relationships among temperature and leaf wetness duration and gray leaf spot incidence and severity. Significant effects were included in a regression model that described the relationship. The polynomial model included linear, quadratic, and cubic terms for temperature and leaf wetness duration effects. The adjusted coefficients of determination for the fitted model for disease incidence and severity were 0.84 and 0.87, respectively. The predictive model may be used as part of an integrated gray leaf spot forecasting system for perennial ryegrass turf.
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U2 - 10.1094/PHYTO.2003.93.3.336
DO - 10.1094/PHYTO.2003.93.3.336
M3 - Article
C2 - 18944344
AN - SCOPUS:0037369623
SN - 0031-949X
VL - 93
SP - 336
EP - 343
JO - PHYTOPATHOLOGY
JF - PHYTOPATHOLOGY
IS - 3
ER -