scholarly journals Influence of Management Practices on Rhizoctonia Large Patch Disease in Zoysiagrass

HortScience ◽  
1994 ◽  
Vol 29 (3) ◽  
pp. 186-188 ◽  
Author(s):  
D.E. Green ◽  
J.D. Fry ◽  
J.C. Pair ◽  
N.A. Tisserat
Keyword(s):  
Rhizoctonia Solani ◽  
Disease Severity ◽  
Management Practices ◽  
Field Studies ◽  
Large Patch ◽  
N Sources ◽  
N Source ◽  
Application Rates ◽  
Patch Disease ◽  
Preemergence Herbicides

Mowing heights from 1.2 to 5.1 cm, five N sources with two application rates (74 and 148 kg N/ha per year), and seven preemergence herbicides were evaluated in field studies in Manhattan and Wichita, Kan., for their effect on large patch disease, caused by Rhizoctonia solani Kuhn AG 2-2, in zoysiagrass (Zoysia spp.). Turf mowed at 1.2 and 2.5 cm was more severely blighted than turf mowed at 4.5 or 5.1 cm. At all mowing heights, turf recovered by August or September. Disease severity was not influenced by N source, N rate, or preemergence herbicides.

scholarly journals Isolation of Pythium Species from Zoysia Grass and Their Effect on Severity of Large Patch Disease

Plant Disease ◽  
1999 ◽  
Vol 83 (2) ◽  
pp. 171-175 ◽  
Author(s):  
A. Aoyagi ◽  
K. Kageyama ◽  
M. Hyakumachi
Keyword(s):  
Rhizoctonia Solani ◽  
Disease Severity ◽  
Golf Courses ◽  
Pythium Species ◽  
Symptom Development ◽  
Large Patch ◽  
Disease Symptoms ◽  
History Of ◽  
Patch Disease

Pythium periplocum, P. rostratum, P. torulosum, and P. vanterpoolii were predominant Pythium species isolated from nine sites with a history of large patch disease of zoysia grass. Rhizoctonia solani AG2-2 LP and the Pythium species were isolated from 21 sod samples of zoysia grass exhibiting large patch symptoms in five golf courses. R. solani AG2-2 LP was obtained from all samples, while P. periplocum, P. rostratum, P. torulosum, and P. vanterpoolii were obtained from 14, 6, 11, and 8 samples, respectively. At least one of the four Pythium species was recovered from 19 samples. To verify pathogenicity of these four species of Pythium on zoysia grass, they were inoculated alone and together with R. solani AG2-2 LP on zoysia grass. When individual isolates were used to inoculate zoysia grass, R. solani AG2-2 LP, P. periplocum, and P. vanterpoolii were moderately aggressive, while P. torulosum and P. rostratum caused little or no disease. Symptoms produced by R. solani AG2-2 LP included orange discoloration of the sheath, and the sheath was easily pulled from the crown. P. periplocum and P. vanterpoolii induced only sheath chlorosis, and the sheath was not easily removed from the crown. In coinoculation tests, the combination of R. solani AG2-2 LP and P. torulosum intensified disease severity on zoysia grass and induced more rapid symptom development than did R. solani AG2-2 LP alone. The combination of R. solani AG2-2 LP and P. periplocum or P. vanterpoolii resulted in sheath necrosis and bare patches, similar to large patch symptoms observed on golf courses.

scholarly journals The Effect of Composted Organic Wastes on Weed Control Provided by Preemergence Herbicides

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 470E-470
Author(s):  
Jennifer A. Johnson ◽  
Larry Kuhns ◽  
Tracey Harpster
Keyword(s):  
Organic Matter ◽  
Sewage Sludge ◽  
Weed Control ◽  
Dry Weight ◽  
Field Studies ◽  
Silty Clay ◽  
Yard Waste ◽  
Application Rates ◽  
Preemergence Herbicides ◽  
Composted Sewage Sludge

Community waste management programs that include the composting of sewage sludge and yard wastes have become a necessity. Using these composts provides many benefits; however, increased levels of organic matter may reduce the effectiveness of preemergence herbicides. Determining how herbicide application rates may need to be adjusted when composted waste is incorporated into the soil may permit the use of these amendments without any decrease in weed control. This experiment examined the effect of two types of compost (composted sewage sludge and composted yard waste) on the weed control provided by four preemergence herbicides. The soil was a Hagerstown silt loam amended with 10%, 20%, or 30% compost by volume. Each mix was placed in half-gallon cardboard milk cartons. The cartons were seeded at 1/2 and 1/4 inches with a mixture of broadleaved weeds and grasses. Each soil mix was treated with simazine, oxyfluorfen, oryzalin, and metolachlor at two rates. Control was evaluated both visually by number and by the dry weight of the harvested weeds. Preliminary results indicate composted sewage sludge causes a greater reduction in herbicide efficacy than composted yard waste. Oryzalin and metolachlor were affected less than oxyfluorfen or simazine. The experiment was repeated using lower application rates. In one replication the soil mixes from the previous experiment were used. The second replication used a Hagerstown silty clay loam soil with fresh compost. The results of this experiment will provide preliminary information for future field studies designed to determine if the application rates of preemergence herbicides need to be adjusted when fields are amended with composted organic matter.

scholarly journals Characterization and Survival of Rhizoctonia solani AG2-2 LP Associated with Large Patch Disease of Zoysia Grass

Plant Disease ◽  
1998 ◽  
Vol 82 (8) ◽  
pp. 857-863 ◽  
Author(s):  
T. Aoyagi ◽  
K. Kageyama ◽  
M. Hyakumachi
Keyword(s):  
Rhizoctonia Solani ◽  
Early Spring ◽  
Optimum Temperature ◽  
Cultural Characteristics ◽  
Large Patch ◽  
Disease Occurrence ◽  
History Of ◽  
Healthy Area ◽  
Patch Disease ◽  
Irregular Cluster

Prevalence and sites of survival of Rhizoctonia solani AG2-2 LP were studied in zoysia grass for 6 years. AG2-2 LP isolates commonly were recovered over all seasons at sites with a history of large patch disease. In patch margins, AG2-2 LP isolates were recovered from crowns of zoysia grass regardless of whether the disease occurred, but were most frequently isolated from the sheath tissues during disease occurrence. In healthy sites approximately 30 cm from the patch, isolates were obtained before but not during disease occurrence. Once disease occurred, patch symptoms rapidly expanded to the edge of tissue colonized by the pathogen during autumn to early spring. To verify that the pathogen spread to healthy areas, the clonal relationship among isolates was examined using their anastomosis reaction. Isolates recovered from the patch and healthy area outside the patch were of the same clone, but isolates from different patches differed. Cultural characteristics and pathogenicity of the AG2-2 LP isolates were compared with R. solani AG2-2 IIIB and R. solani AG2-2 IV. The AG2-2 LP isolates showed an irregular cluster of mycelia (not sclerotia), an irregular zonation, dark brown main hyphae, and sparse aerial hyphae on potato dextrose agar after 4 weeks of incubation. Optimum temperature for growth was 23°C. Cultural characteristics of AG2-2 subgroups IIIB and IV differed from LP isolates. All isolates of AG2-2 LP caused moderate to high levels of disease on zoysia grass, but were nonpathogenic or caused little disease on bent grass and sugar beet. These results indicate that cultural characteristics and host range of AG2-2 LP are different than those of AG2-2 IIIB and AG2-2 IV.

First report of Rhizoctonia solani AG-2-2 IV causing large patch disease of Japanese lawn grass in India

2020 ◽  
Vol 102 (4) ◽  
pp. 1351-1352
Author(s):  
Arghya Banerjee ◽  
Saidul Islam ◽  
Koushik Banerjee ◽  
Debashis Rana ◽  
Krishna Ray ◽  
...  
Keyword(s):  
Rhizoctonia Solani ◽  
Large Patch ◽  
First Report ◽  
Patch Disease

scholarly journals Cabbage Yield and Glucosinolate Concentrations as Affected by Nitrogen and Sulfur Fertility

HortScience ◽  
2005 ◽  
Vol 40 (5) ◽  
pp. 1493-1498 ◽  
Author(s):  
C.J. Rosen ◽  
V.A. Fritz ◽  
G.M. Gardner ◽  
S.S. Hecht ◽  
S.G. Carmella ◽  
...  
Keyword(s):  
Management Practices ◽  
Field Studies ◽  
Fertilizer Application ◽  
Interactive Effects ◽  
Available N ◽  
Cultural Management ◽  
Application Rates ◽  
Glucosinolate Concentration ◽  
Cruciferous Plants ◽  
S Application

Glucosinolates are a class of nitrogen (N) and sulfur (S) containing compounds shown to have cancer-preventing properties in animal models and widely found in cruciferous plants. The overall objective of this study was to determine whether N and S fertility affects glucosinolate concentrations in cabbage (Brassica oleracea L. Capitata group). Field studies on a sandy soil low in available N and S were conducted over a 2-year period with both green (`Grand Slam') and red (`Vorox') cabbage cultivars. Treatments evaluated each year were the interactive effects of N (125 and 250 kg·ha–1) and S (0, and 110 kg·ha–1) fertilizer application. Yield of both cabbage cultivars increased with increasing N and S in the second year of the study, but not in the first. Tissue N concentrations in heads at harvest increased with N application and tissue S concentrations increased with S application. When S was not applied, tissue S decreased significantly as N rate increased, while N rate had no effect on tissue S concentrations when S was applied. The dominant glucosinolate detected in both cabbage cultivars was glucobrassicin, with indole forms accounting for about 80% of the total glucosinolates regardless of treatment. Tissue N was negatively correlated and tissue S and S to N ratio were positively correlated with total glucosinolate concentration, although all correlations were generally weak (r2 < 0.5). Total glucosinolates and glucobrassicin concentrations were maximized in both cultivars at the low N and high S application rates. Except for sinigrin in one of the 2 years, all glucosinolates detected were higher in Vorox than in `Grand Slam'. Based on these results, glucosinolates in cabbage can be manipulated by cultural management practices as well as genetics.

scholarly journals Desert Lettuce Responds to N Rate but Not N Source

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 446A-446
Author(s):  
C.A. Sanchez ◽  
N. Obeker
Keyword(s):  
Calcium Nitrate ◽  
Growing Season ◽  
Field Studies ◽  
Marketable Yield ◽  
N Accumulation ◽  
N Sources ◽  
Iceberg Lettuce ◽  
N Source ◽  
Soil Temperatures ◽  
Lettuce Growth

Approximately 30,000 ha of iceberg lettuce (Lactuca sativa L.) are produced in the low desert region of the southwestern United States during the fall–winter–spring period each year. During this period, soil temperatures in lettuce beds range from 10 to 30°C. During the cooler part of the growing season, growers typically use nitrate-N sources because they believe they are generally more available for plant uptake. However, limited experimental evidence exists to support this practice. Three field studies were conducted during the 1994–1995 growing season to evaluate the response of iceberg lettuce to N rate and N source. The N sources urea, ammonium sulfate, ammonium nitrate, and calcium nitrate were applied at rates ranging from 0 to 300 kg N/ha. Although lettuce growth, N accumulation, and marketable yield significantly increased by N rate, there were generally no differences due to N source.

Detection of Rhizoctonia solani AG-2-2 IV, the Causal Agent of Large Patch of Zoysiagrass, Using Plasmid DNA as a Probe.

1998 ◽  
Vol 64 (5) ◽  
pp. 451-457 ◽  
Author(s):  
Susumu TAKAMATSU ◽  
Manami NAKANO ◽  
Hideyuki YOKOTA ◽  
Hitoshi KUNOH
Keyword(s):  
Rhizoctonia Solani ◽  
Plasmid Dna ◽  
Causal Agent ◽  
Large Patch

scholarly journals Prediction of leaching and groundwater contamination by pesticides

2006 ◽  
Vol 78 (5) ◽  
pp. 1081-1090 ◽  
Author(s):  
Werner Kördel ◽  
Michael Klein
Keyword(s):  
Maximum Concentration ◽  
Management Practices ◽  
Preferential Flow ◽  
Soil Depth ◽  
Sandy Soils ◽  
Field Studies ◽  
Macropore Flow ◽  
Eu Directive ◽  
Present Information ◽  
Silty Soils

Herein, we describe how pesticide leaching is assessed in Europe in order to fulfill EU Directive 91/414. The assessment schemes were developed to protect groundwater from unacceptable effects caused by pesticide use. They presently focus on chromatographic flow processes, which are dominant in sandy soils. Nevertheless, important regions in Europe are characterized by structured soils where transport through macropores is most relevant.Comparison of parallel field studies with isoproturon performed in sandy and silty soils showed that maximum concentration in the structured soil at a soil depth of 1 m may exceed respective concentrations in sandy soils by a factor of 60. Similar results were obtained by lysimeter studies using silty soil cores with maximum concentration of 40 μg/l at the soil bottom. These results demonstrate that preferential flow is more the rule than the exception in well-structured fine-textured soils, and pesticide losses via macropore flow may exceed losses via matrix transport considerably. All present information available for macropore flow suggest the need for greater regional assessments. Other recommendations include analysis of the influence of different soil management practices on the formation of macropores.

scholarly journals Development of Bacterial Spot on Near-Isogenic Lines of Bell Pepper Carrying Gene Pyramids Composed of Defeated Major Resistance Genes

1999 ◽  
Vol 89 (11) ◽  
pp. 1066-1072 ◽  
Author(s):  
C. S. Kousik ◽  
D. F. Ritchie
Keyword(s):  
Disease Severity ◽  
Resistance Genes ◽  
Field Studies ◽  
Residual Effects ◽  
Specific Gene ◽  
Near Isogenic Lines ◽  
Bacterial Spot ◽  
Isogenic Lines ◽  
Major Resistance Genes ◽  
Race 4

Disease severity caused by races 1 through 6 of Xanthomonas campestris pv. vesicatoria on eight near-isogenic lines (isolines) of Early Calwonder (ECW) with three major resistance genes (Bs1, Bs2, and Bs3) in different combinations was evaluated in the greenhouse and field. Strains representing races 1, 3, 4, and 6 caused similar high levels of disease severity, followed by races 2 and 5 on susceptible ECW. Race 3 caused severe disease on all isolines lacking resistance gene Bs2. Race 4, which defeats Bs1 and Bs2, caused less disease on isoline ECW-12R (carries Bs1 + Bs2), than on isolines ECW, ECW-10R (carries Bs1), and ECW-20R (carries Bs2). Similar results were obtained with race 4 strains in field studies conducted during 1997 and 1998. In greenhouse studies, race 6, which defeats all three major genes, caused less disease on isoline ECW-13R (carries Bs1 + Bs3) and ECW-123R (carries Bs1 + Bs2 + Bs3) than on isolines ECW, ECW-10R, ECW-20R, and ECW-30R (carries Bs3), but not on ECW-23R (carries Bs2 + Bs3). In greenhouse studies with commercial hybrids, strains of races 4 and 6 caused less disease on Boynton Bell (carries Bs1 + Bs2) than on Camelot (carries no known resistance genes), King Arthur (carries Bs1), and X3R Camelot (carries Bs2). Race 6 caused less disease on hybrid R6015 (carries Bs1 + Bs2 + Bs3) and Sentinel (carries Bs1 + Bs3) than on Camelot. Residual effects were not as evident in field studies with race 6 strains. Defeated major resistance genes deployed in specific gene combinations (i.e., gene pyramids) were associated with less area under the disease progress curve than when genes were deployed individually in isolines of ECW or commercial hybrids. Successful management of bacterial spot of pepper is achieved incrementally by integrating multiple tactics. Although there is evidence of residual effects from defeated genes, these effects alone likely will not provide acceptable bacterial spot control in commercial production fields. However, when combined with sanitation practices and a judicious spray program, pyramids of defeated resistance genes may aid in reducing the risk of major losses due to bacterial spot.

Effects of straw incorporation on Rhizoctonia solani inoculum in paddy soil and rice sheath blight severity

2013 ◽  
Vol 152 (5) ◽  
pp. 741-748 ◽  
Author(s):  
H. ZHU ◽  
Z. X. WANG ◽  
X. M. LUO ◽  
J. X. SONG ◽  
B. HUANG
Keyword(s):  
Rhizoctonia Solani ◽  
Disease Severity ◽  
Rice Straw ◽  
Paddy Soil ◽  
Sheath Blight ◽  
Soil Productivity ◽  
Rice Sheath Blight ◽  
Important Method ◽  
Pathogen Dynamics ◽  
Straw Incorporation

SUMMARYIncorporation of rice straw into soil has traditionally been an important method of recycling nutrients and improving soil productivity. Currently, although the effects of straw incorporation on disease severity have been documented, the dynamics of the pathogen in soil after straw incorporation are poorly understood. In the present study, rice straw with various proportions of diseased straw was incorporated at three separate locations (SuPu town, SuSong County and FengYang County) in Anhui province, China. The pathogen dynamics in paddy soil and disease severity of sheath blight during two continuous years from April 2010 to April 2012 were investigated. For all three locations, the amount of pathogen inoculum that persisted in the soil increased with increases in the proportion of diseased straw incorporated. Incorporation of 0·3 and 0·5 diseased straw into soil increased the amount of pathogen inoculum in the soil significantly, whereas incorporation of 0·1 diseased straw into soil had no significant effect on the pathogen inoculum compared with the control (no straw incorporated) or disease severity. Incorporation of healthy rice straw (no disease) resulted in a significant decrease in disease severity, whereas proportions of 0·3 and 0·5 diseased straw resulted in a significant increase of disease severity compared with the control. These results suggested that incorporation of diseased straw enhanced pathogen numbers in soil during the whole decomposition period and increased disease severity. To avoid soil-borne disease accumulation, severely diseased straw should be removed from the field or pre-treated before incorporation.

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