scholarly journals Synergistic/antagonistic interactions between Neopseudocercosporella , Alternaria , Leptosphaeria and Hyaloperonospora determine aggregate foliar disease severity in rapeseed

2021 ◽  
Author(s):  
Tamsal Murtza ◽  
Ming Pei You ◽  
Martin J. Barbetti
Keyword(s):  
Disease Severity ◽  
Foliar Disease ◽  
Antagonistic Interactions

scholarly journals Meta-Analysis of Yield Response of Hybrid Field Corn to Foliar Fungicides in the U.S. Corn Belt

2011 ◽  
Vol 101 (9) ◽  
pp. 1122-1132 ◽  
Author(s):  
P. A. Paul ◽  
L. V. Madden ◽  
C. A. Bradley ◽  
A. E. Robertson ◽  
G. P. Munkvold ◽  
...  
Keyword(s):  
United States ◽  
Disease Severity ◽  
Meta Analysis ◽  
The United States ◽  
Yield Response ◽  
Foliar Disease ◽  
Yield Increase ◽  
Field Corn ◽  
Yield Difference ◽  
Meta Analyses

The use of foliar fungicides on field corn has increased greatly over the past 5 years in the United States in an attempt to increase yields, despite limited evidence that use of the fungicides is consistently profitable. To assess the value of using fungicides in grain corn production, random-effects meta-analyses were performed on results from foliar fungicide experiments conducted during 2002 to 2009 in 14 states across the United States to determine the mean yield response to the fungicides azoxystrobin, pyraclostrobin, propiconazole + trifloxystrobin, and propiconazole + azoxystrobin. For all fungicides, the yield difference between treated and nontreated plots was highly variable among studies. All four fungicides resulted in a significant mean yield increase relative to the nontreated plots (P < 0.05). Mean yield difference was highest for propiconazole + trifloxystrobin (390 kg/ha), followed by propiconazole + azoxystrobin (331 kg/ha) and pyraclostrobin (256 kg/ha), and lowest for azoxystrobin (230 kg/ha). Baseline yield (mean yield in the nontreated plots) had a significant effect on yield for propiconazole + azoxystrobin (P < 0.05), whereas baseline foliar disease severity (mean severity in the nontreated plots) significantly affected the yield response to pyraclostrobin, propiconazole + trifloxystrobin, and propiconazole + azoxystrobin but not to azoxystrobin. Mean yield difference was generally higher in the lowest yield and higher disease severity categories than in the highest yield and lower disease categories. The probability of failing to recover the fungicide application cost (ploss) also was estimated for a range of grain corn prices and application costs. At the 10-year average corn grain price of $0.12/kg ($2.97/bushel) and application costs of $40 to 95/ha, ploss for disease severity <5% was 0.55 to 0.98 for pyraclostrobin, 0.62 to 0.93 for propiconazole + trifloxystrobin, 0.58 to 0.89 for propiconazole + azoxystrobin, and 0.91 to 0.99 for azoxystrobin. When disease severity was >5%, the corresponding probabilities were 0.36 to 95, 0.25 to 0.69, 0.25 to 0.64, and 0.37 to 0.98 for the four fungicides. In conclusion, the high ploss values found in most scenarios suggest that the use of these foliar fungicides is unlikely to be profitable when foliar disease severity is low and yield expectation is high.

scholarly journals Reaction of Selected Soybean Genotypes to Isolates of Fusarium solani f. sp. glycines and Their Culture Filtrates

Plant Disease ◽  
1998 ◽  
Vol 82 (9) ◽  
pp. 999-1002 ◽  
Author(s):  
Y. H. Huang ◽  
G. L. Hartman
Keyword(s):  
Great Lakes ◽  
Disease Severity ◽  
Culture Filtrate ◽  
Fusarium Solani ◽  
Stem Length ◽  
Soybean Plant ◽  
Foliar Disease ◽  
Plant Introductions ◽  
Disease Progress ◽  
Progress Curve

Four soybean plant introductions, PI 520.733, PI 567.374, PI 567.650B, and PI 567.659, and one soybean cultivar, Great Lakes 3202, were inoculated under greenhouse conditions with four isolates of Fusarium solani f. sp. glycines. Foliar disease severity rating was greatest on PI 567.659, followed by Great Lakes 3202, PI 520.733, PI 567.650B, and PI 567.374. There was no significant interaction between isolates and soybean entries for foliar disease severity ratings. Experiments also were conducted to determine if disease development and root colonization differed among entries. Root infection of the five entries did not differ (P = 0.05). Foliar disease progress curves increased faster for PI 567.659 and Great Lakes 3202 than for PI 567.374. The area under the disease progress curve (AUDPC) value for PI 567.374 was the lowest and differed (P = 0.01) from AUDPC values for Great Lakes 3202 and PI 567.659. There were no differences (P = 0.01) in length of taproot lesions, losses in root dry weight, and vascular stem length discoloration among the entries, and there was no correlation (P = 0.05) between these measurements and foliar AUDPC values. Cut seedling stems immersed in culture filtrate developed interveinal chlorosis on leaves of each entry within 2 days. Disease severity on cut seedlings of PI 567.374 was lower (P = 0.01) than on the other entries. There was a positive correlation (r = 0.94, P = 0.05) between AUDPC values of the five entries inoculated with the fungus and the cut seedling test using culture filtrate.

The impact of fungicide and herbicide timing on foliar disease severity, and barley productivity and quality

2015 ◽  
Vol 95 (3) ◽  
pp. 525-537 ◽  
Author(s):  
T. K. Turkington ◽  
J. T. O'Donovan ◽  
K. N. Harker ◽  
K. Xi ◽  
R. E. Blackshaw ◽  
...  
Keyword(s):  
Disease Severity ◽  
Foliar Disease ◽  
Herbicide Timing ◽  
The Impact

Managing crop losses from foliar diseases with fungicides, rotation, and tillage in the Saskatchewan Parkland

2000 ◽  
Vol 80 (1) ◽  
pp. 169-175 ◽  
Author(s):  
K. L. Bailey ◽  
A. M. Johnston ◽  
H. R. Kutcher ◽  
B. D. Gossen ◽  
R. A. A. Morrall
Keyword(s):  
Disease Severity ◽  
Seed Weight ◽  
Crop Diversity ◽  
Stem Rot ◽  
Yield Response ◽  
Reduced Tillage ◽  
Leaf Spot Disease ◽  
Sclerotinia Stem Rot ◽  
Crop Losses ◽  
Foliar Disease

The effects of three tillage systems, three crop rotations, and fungicide applications were evaluated on diseases of barley, wheat, canola and pea at Melfort, SK, from 1994 to 1998. During these years, reduced tillage did not increase crop losses due to diseases. Four-year rotations with higher proportions of broad-leaved crops and more crop diversity (i.e., canola, pea, flax, and barley) had higher yields than rotations with fewer broad-leaved crops and less crop diversity (i.e., canola, wheat, barley, and barley). However, these rotations did not influence the severity of septoria leaf blotch of wheat, net blotch of barley, the incidence of sclerotinia stem rot and blackleg of canola, or the severity of mycosphaerella blight of pea. Interplot interference may have been a factor influencing some diseases in plots, as the size was only 270 m2. Fungicide application of propiconazole on Harrington barley decreased foliar disease severity and increased yield by 23%, seed weight by 13%, and kernel plumpness by 25%. Application of azoxystrobin decreased foliar disease and increased pea yield 29% and seed weight by 7% for the pea cultivars Express and Highlight. Foliar disease severity on AC Taber wheat was reduced by application of propiconazole in 2 of 4 yr, but the yield response was very inconsistent. Similarly, AC Excel canola had inconsistent disease and yield response to applications of propiconazole and benomyl, but levels of sclerotinia stem rot and blackleg were very low in all years. These results indicate that reduced tillage will not result in significantly higher levels of disease that require fungicide inputs to maintain yield. Moving from cereal-based rotations to more diverse, broad-leaved based rotations improves the yield of cereals. However, regardless of tillage or rotation, higher yields may be obtained in barley and pea with fungicides for control of leaf spot disease in susceptible cultivars. Key words: Plant disease, rotation, tillage, fungicides, yield loss

scholarly journals Effects of Pathogen Population Levels and Crop-Derived Nutrients on Development of Soybean Sudden Death Syndrome and Growth of Fusarium virguliforme

Plant Disease ◽  
2017 ◽  
Vol 101 (3) ◽  
pp. 434-441 ◽  
Author(s):  
Gretchen M. Freed ◽  
Crystal M. Floyd ◽  
Dean K. Malvick
Keyword(s):  
Sudden Death ◽  
Disease Severity ◽  
Root Rot ◽  
Crop Residues ◽  
Disease Risk ◽  
Sudden Death Syndrome ◽  
Pathogen Population ◽  
Fusarium Virguliforme ◽  
Foliar Disease ◽  
Corn Seed

Sudden death syndrome (SDS) of soybean, caused by Fusarium virguliforme, is a significant disease of soybean. The suite of factors that influence disease development is incompletely understood. The goal of this study was to determine the effects of pathogen population levels, crop residues, seed exudates, and their interactions on development of SDS and growth of F. virguliforme. Studies were conducted in a greenhouse with cultivars susceptible and partially resistant to SDS, four pathogen population levels, and six crop residue treatments (none; ground corn seed, stalks, and roots; ground soybean stems; and sorghum seed). Root rot was assessed 15 and 50 days after inoculation (dai) and foliar disease and plant biomass were assessed 50 dai. Population level increases and crop residues had significant interacting effects on increasing foliar disease severity and root rot and on biomass reduction. Disease severity was positively correlated with population and biomass was negatively correlated. Plants grown with no crop residues exhibited low or no root rot or foliar disease 15 dai, and severity was greatest with corn and sorghum seed. In vitro studies were conducted to test the effects of exudates collected from germinating soybean and corn seed on growth of F. virguliforme and F. solani. Growth of these fungi was greater in exudates than in water. More growth occurred in exudates collected during soybean radicle emergence than those sampled at other times during germination. These studies show that pathogen population levels and crop-derived nutrients in soil interact and influence severity of SDS. Results have implications for gaging disease risk and managing SDS.

scholarly journals Evaluation of TOM-CAST in Timing Fungicide Sprays for Management of Alternaria Blight on American Ginseng

Plant Disease ◽  
2008 ◽  
Vol 92 (12) ◽  
pp. 1611-1615 ◽  
Author(s):  
S. N. Hill ◽  
M. K. Hausbeck
Keyword(s):  
Disease Severity ◽  
Seed Yield ◽  
American Ginseng ◽  
Treatment Programs ◽  
Panax Quinquefolium ◽  
Copper Hydroxide ◽  
Foliar Disease ◽  
Yield And Quality ◽  
Alternaria Panax ◽  
Seed Coats

Alternaria panax incites blighting of the foliage, peduncles, and drupes of cultivated American ginseng (Panax quinquefolium). A disease forecaster (TOM-CAST), originally developed to predict leaf blight caused by A. solani on tomato, was evaluated for management of A. panax in commercial ginseng gardens. For 3 years, fungicide sprays initiated by TOM-CAST (using 10 and 15 disease severity value thresholds) were compared with sprays applied at 7- and 10-day intervals. Three fungicide programs were evaluated: (i) chlorothalonil alone, (ii) chlorothalonil alternated with pyraclostrobin, and (iii) copper hydroxide alternated with pyraclostrobin. As many as 10 fewer fungicide applications were made when using TOM-CAST or the 10-day programs. Although select TOM-CAST treatment programs were comparable with the 7-day schedule in limiting foliar disease, only the 7-day applications adequately protected drupe and seed yield. Both A. panax and A. alternata were recovered from drupe tissues and seed coats. Only A. alternata was recovered from endosperm halves. Ginseng seed yield and quality is an important consideration when assessing fungicide programs.

scholarly journals RGB-based phenotyping of foliar disease severity under controlled conditions

2021 ◽  
Author(s):  
Kaique S. Alves ◽  
Mariana Guimarães ◽  
João Paulo Ascari ◽  
Marcia F. Queiroz ◽  
Rafael F. Alfenas ◽  
...  
Keyword(s):  
Disease Severity ◽  
Foliar Disease ◽  
Controlled Conditions
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