scholarly journals Spring Dead Spot Occurrence in Bermudagrass following Fungicide and Nutrient Applications

HortScience ◽  
1992 ◽  
Vol 27 (10) ◽  
pp. 1092-1093 ◽  
Author(s):  
Lambert B. McCarty ◽  
Leon T. Lucas ◽  
Joseph M. DiPaola
Keyword(s):  
Management Practices ◽  
Cynodon Dactylon ◽  
Control Measures ◽  
Disease Suppression ◽  
Potassium Sulfate ◽  
Gaeumannomyces Graminis ◽  
Spring Dead Spot ◽  
Late Fall ◽  
Serious Disease ◽  
Fall Application

Spring dead spot (SDS) [Gaeumannomyces graminis (Sacc.) von Arx & D. Olivier var. graminis Walker] is a serious disease of bermudagrass [Cynodon dactylon (L.) Pers.] throughout much of the southern United States and is believed to be at least partially influenced by the previous year's turfgrass management practices. Research was performed to: a) determine the efficacy of selected fungicide control measures; and b) determine the influence of N and K nutrient regimes on the expression of SDS symptoms in Tifway bermudagrass (C. dactylon x C. transvaalensis Burtt-Davy). Averaged over two sites in 2 years, a 72% reduction in SDS followed a fall application of benomyl at 12 kg·ha. Fenarimol applied at three rates (1.5, 2.3, and 3.0 kg·ha) on three fall dates reduced SDS by a combined average of 66%. A single application of propiconazole (2.5 kg·ha) reduced disease by an average of 56%. Application of N (98 kg·ha) in late fall increased SDS 128% in one test location. Application of potassium sulfate (269 kg K/ha) in late fall resulted in an average increase in SDS expression of 89% the following spring over all experiments. Turf managers with severe SDS should minimize heavy late-fall K applications and possibly use benomyl, fenarimol, or propiconazole for disease suppression. Chemical names used: α -(2-chlorophenyl)α -(4-chlorophenyl)-S-pyrimidinemethanol (fenarimol); [methyl 1(butylcarbamoyl)-2-benzimidazolecarbamate] (benomyl); 1-[[2-(2,4-dichlorophenyl)-4propyl-1,3-dioxolan-2-yl]methyl]--1H-1,2,4-triazole (propiconazole).

scholarly journals 017 Evaluating Best Management Practices for Spring Dead Spot Suppression in Bermudagrass

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 390F-391 ◽  
Author(s):  
F. Iriarte ◽  
J. Fry ◽  
N. Tisserat
Keyword(s):  
Best Management Practices ◽  
Management Practices ◽  
Cultural Practices ◽  
Disease Suppression ◽  
Nitrogen Fertilizers ◽  
Spring Dead Spot ◽  
Best Management ◽  
Turf Quality ◽  
Moderate Disease ◽  
Plot Design

Bermudagrass turf quality is commonly reduced in the transition zone by Ophiosphaerella herpotricha, a root-infecting fungus that causes spring dead spot (SDS). Fungicides applied in autumn typically result in poor to moderate disease suppression. Earlier research has indicated that some cultural practices, including core aerification or fertilization with soil acidifying nitrogen fertilizers, may suppress SDS. Our objective was to evaluate several treatment combinations for reducing disease severity. Treatments were arranged in a split-plot design, with whole plots being aerification + verticutting, or no cultivation. Subplots within whole plots consisted of a factorial arrangement of azoxystrobin (one September application of at 0.6 kg·ha-1), trinexapac-ethyl (three summer applications at 6.1 kg·ha-1), and ammonium sulfate (three summer applications with N at 49 kg·ha-1). After 1 year of treatment, spring turf quality was improved in all treatments that included trinexapac-ethyl. Diseased area was reduced from 34% to 21% in plots receiving azoxystrobin + trinexapac-ethyl.

Geographic Distribution of Ophiosphaerella Species in the Mid-Atlantic United States

2021 ◽  
Author(s):  
Wendell Joseph Hutchens ◽  
Caleb Henderson ◽  
Elizabeth A Bush ◽  
James Kerns ◽  
David McCall
Keyword(s):  
United States ◽  
North Carolina ◽  
Geographic Distribution ◽  
Management Practices ◽  
Cynodon Dactylon ◽  
Spring Dead Spot ◽  
Athletic Fields ◽  
Survey Results ◽  
Ophiosphaerella Herpotricha ◽  
Species Specific

Spring dead spot (SDS) of bermudagrass (Cynodon dactylon) is primarily caused by Ophiosphaerella herpotricha and Ophiosphaerella korrae in North America. These two species respond differently to numerous management practices, grow optimally at different soil pH ranges, and differ in aggressiveness. Understanding the Ophiosphaerella species distribution in regions where SDS occurs will allow turfgrass managers to tailor their management practices toward the predominant species present. A survey was conducted in the Mid-Atlantic United States in which one to 14 samples of bermudagrass expressing SDS symptoms were taken from 51 athletic fields, golf courses, or sod farms across Delaware, Maryland, North Carolina, and Virginia. DNA was isolated from necrotic root and stolon tissue, amplified using species-specific primers, and detected in a real-time PCR assay. At least one isolate of O. herpotricha was recovered from 76% of the locations and O. korrae was recovered from 73% of the locations. Ophiosphaerella herpotricha was amplified from 55% of the samples while O. korrae was amplified from 37% of the samples. There were distinct regions in the Mid-Atlantic in which either O. herpotricha or O. korrae was predominant. Ophiosphaerella herpotricha was predominant in western Virginia, central North Carolina as well as Delaware and eastern Maryland. However, O. korrae was predominant in central Maryland and Virginia as well as eastern Virginia and North Carolina. Ophiosphaerella herpotricha was isolated from certain cultivars more frequently than O. korrae and vice versa. These survey results elucidate the geographic distribution of O. herpotricha and O. korrae throughout the Mid-Atlantic United States.

scholarly journals Influence of Fungicide Application Timings on the Management of Bermudagrass Spring Dead Spot Caused by Ophiosphaerella herpotricha

Plant Disease ◽  
2009 ◽  
Vol 93 (12) ◽  
pp. 1341-1345 ◽  
Author(s):  
N. R. Walker
Keyword(s):  
Disease Severity ◽  
Patch Size ◽  
Cynodon Dactylon ◽  
Control Measure ◽  
Cost Effective ◽  
Integrated Approach ◽  
Spring Dead Spot ◽  
Plot Area ◽  
Fall Application ◽  
Important Disease

Spring dead spot, caused by Ophiosphaerella spp., is the most important disease of bermudagrass (Cynodon dactylon and C. dactylon × C. transvaalensis) where cool temperatures induce dormancy. Field plot studies were conducted from 2004 to 2008 to determine the frequency and timings of fungicide applications for control of the disease. The fungicide treatments included tebuconazole applied two, three, or four times in the fall, once in the spring plus twice in the fall, or twice in the spring and twice in the fall. Propiconazole treatments consisted of one spring, one spring and one fall, one spring and two fall, or two fall applications. Disease severity in plots treated three or four times in the fall with tebuconazole was significantly lower than for those not treated. Based on the change in patch size prior to treatment, patches in plots treated four times with tebuconazole were smaller than in the previous year and were smaller than patches treated once in the spring and twice in the fall or twice in the fall. Plots receiving two fall, one spring and one fall, or one spring and two fall applications of propiconazole had less disease than plots treated once in the spring or plots not treated. Based on the change in plot area prior to treatment, plots receiving two fall, one spring and one fall, or one spring and two fall propiconazole applications had a reduction in plot area expressing symptoms of disease. These studies demonstrated that two fall or one spring and one fall application appear to provide the most effective and cost effective disease control in an integrated approach to managing the disease. The study also demonstrates the importance of disease severity assessment prior to treatment in evaluating the efficacy of a control measure for spring dead spot.

Development of Management Strategies for Hop Powdery Mildew in the Pacific Northwest

2001 ◽  
Vol 2 (1) ◽  
pp. 8 ◽  
Author(s):  
William W. Turechek ◽  
Walter F. Mahaffee ◽  
Cynthia M. Ocamb
Keyword(s):  
Powdery Mildew ◽  
Pacific Northwest ◽  
Management Practices ◽  
Management Strategies ◽  
Control Measures ◽  
Laboratory Studies ◽  
The Pacific ◽  
Sphaerotheca Macularis ◽  
Serious Disease ◽  
Sound Management

Hop powdery mildew, caused by Sphaerotheca macularis, was first discovered in the Yakima Valley of Washington in 1997 and has since become the most serious disease of hop (Humulus lupus) in the Pacific Northwest. Lack of understanding of the epidemiology of S. macularis has made it difficult to develop sound management practices. Results from our field and laboratory studies suggest that control measures applied early in the growing season are probably the most important in shaping the epidemic in a particular field and that late season control measures may not need to be applied at the same intensity as in early to mid-season. Accepted for publication 9 March 2001. Published 13 March 2001.

Climate resilience in rural Zambia: evaluating farmers’ response to El Niño-induced drought

2021 ◽  
pp. 1-23
Author(s):  
Federica Alfani ◽  
Aslihan Arslan ◽  
Nancy McCarthy ◽  
Romina Cavatassi ◽  
Nicholas Sitko
Keyword(s):  
El Niño ◽  
Management Practices ◽  
Unobserved Heterogeneity ◽  
El Nino ◽  
Control Measures ◽  
Data Set ◽  
Climate Resilience ◽  
Diversification Strategies ◽  
Household Incomes ◽  
Rural Zambia

Abstract This paper aims at identifying whether and how sustainable land management practices and livelihood diversification strategies have contributed to moderating the impacts of the El Niño-related drought in Zambia. This is done using a specifically designed survey called the El Niño Impact Assessment Survey, which is combined with the Rural Agricultural Livelihoods Surveys, as well as high resolution rainfall data at the ward level over 34 years. This unique panel data set allows us to control for the time-invariant unobserved heterogeneity to understand the impacts of shocks like El Niño, which are expected to become more frequent and severe as a result of climate change. We find that maize yields were substantially reduced and that household incomes were only partially protected from the shock thanks to diversification strategies. Mechanical erosion control measures and livestock diversification emerge as the only strategies that provided yield and income benefits under weather shock.

scholarly journals Constraints to Pearl Millet (Pennisetum glaucum) Production and Farmers’ Approaches to Striga hermonthica Management in Burkina Faso

2021 ◽  
Vol 13 (15) ◽  
pp. 8460
Author(s):  
Armel Rouamba ◽  
Hussein Shimelis ◽  
Inoussa Drabo ◽  
Mark Laing ◽  
Prakash Gangashetty ◽  
...  
Keyword(s):  
Burkina Faso ◽  
Pearl Millet ◽  
Management Practices ◽  
Pennisetum Glaucum ◽  
Control Measures ◽  
Striga Hermonthica ◽  
Soil Conditions ◽  
Management Options ◽  
Central Plateau ◽  
South Central

Pearl millet (Pennisetum glaucum) is a staple food crop in Burkina Faso that is widely grown in the Sahelian and Sudano-Sahelian zones, characterised by poor soil conditions and erratic rainfall, and high temperatures. The objective of this study was to document farmers’ perceptions of the prevailing constraints affecting pearl millet production and related approaches to manage the parasitic weeds S. hermonthica. The study was conducted in the Sahel, Sudano-Sahelian zones in the North, North Central, West Central, Central Plateau, and South Central of Burkina Faso. Data were collected through a structured questionnaire and focus group discussions involving 492 participant farmers. Recurrent drought, S. hermonthica infestation, shortage of labour, lack of fertilisers, lack of cash, and the use of low-yielding varieties were the main challenges hindering pearl millet production in the study areas. The majority of the respondents (40%) ranked S. hermonthica infestation as the primary constraint affecting pearl millet production. Respondent farmers reported yield losses of up to 80% due to S. hermonthica infestation. 61.4% of the respondents in the study areas had achieved a mean pearl millet yields of <1 t/ha. Poor access and the high cost of introduced seed, and a lack of farmers preferred traits in the existing introduced pearl millet varieties were the main reasons for their low adoption, as reported by 32% of respondents. S. hermonthica management options in pearl millet production fields included moisture conservation using terraces, manual hoeing, hand weeding, use of microplots locally referred to as ‘zaï’, crop rotation and mulching. These management techniques were ineffective because they do not suppress the below ground S. hermonthica seed, and they are difficult to implement. Integrated management practices employing breeding for S. hermonthica resistant varieties with the aforementioned control measures could offer a sustainable solution for S. hermonthica management and improved pearl millet productivity in Burkina Faso.

Seasonal Nonstructural Carbohydrate Patterns in Dewberry (Rubus spp.) Roots

Weed Science ◽  
2021 ◽  
pp. 1-23
Author(s):  
Katherine M. Ghantous ◽  
Hilary A. Sandler
Keyword(s):  
Weed Management ◽  
Management Practices ◽  
Soluble Sugars ◽  
Leaf Expansion ◽  
Control Measures ◽  
Growth Stages ◽  
Phenological Stages ◽  
Long Term Storage ◽  
Nonstructural Carbohydrate ◽  
Fruit Maturity

Abstract Applying control measures when carbohydrate levels are low can decrease the likelihood of plant survival, but little is known about the carbohydrate cycles of dewberry (Rubus spp.), a problematic weed group on cranberry farms. Weedy Rubus plants were collected from areas adjacent to production beds on commercial cranberry farms in Massachusetts, two locations per year for two years. For each site and year, four entire plants were collected at five phenological stages: budbreak, full leaf expansion, flowering, fruit maturity, and after onset of dormancy. Root sections were analyzed for total nonstructural carbohydrate (TNC; starch, sucrose, fructose, and glucose). Overall trends for all sites and years showed TNC were lowest at full leaf expansion or flowering; when sampled at dormancy, TNC concentrations were greater than or equal to those measured at budbreak. Starch, a carbohydrate form associated with long-term storage, had low levels at budbreak, leaf expansion and/or flowering with a significant increase at fruit maturity and the onset of dormancy, ending at levels higher than those found at budbreak. The concentration of soluble sugars, carbohydrate forms readily usable by plants, was highest at budbreak compared to the other four phenological samplings. Overall, our findings supported the hypothesis that TNC levels within the roots of weedy Rubus plants can be predicted based on different phenological growth stages in Massachusetts. However, recommendations for timing management practices cannot be based on TNC cycles alone; other factors such as temporal proximity to dormancy may also impact Rubus plants recovery and further research is warranted. Late-season damage should allow less time for plants to replenish carbohydrate reserves (prior to the onset of dormancy), thereby likely enhancing weed management tactics effectiveness over time. Future studies should consider tracking the relationship between environmental conditions, phenological stages, and carbohydrate trends.

scholarly journals Performance Assessment of Erosion Remediation Measures and Proposal of The Best Management Practices for Erosion Control in Sebeya Catchment, Rwanda

2020 ◽  
Vol 3 (2) ◽  
Author(s):  
Félicien Majoro ◽  
Umaru Garba Wali ◽  
Omar Munyaneza ◽  
François-Xavier Naramabuye ◽  
Concilie Mukamwambali
Keyword(s):  
Soil Erosion ◽  
Best Management Practices ◽  
Management Practices ◽  
Soil Depth ◽  
Erosion Control ◽  
Control Measures ◽  
Tree Planting ◽  
Best Management ◽  
Remediation Measures ◽  
Soil Erosion Control

Soil erosion is an environmental concern that affects agriculture, wildlife and water bodies. Soil erosion can be avoided by maintaining a protective cover on the soil to create a barrier to the erosive agent or by modifying the landscape to control runoff amounts and rates. This research is focused on Sebeya catchment located in the Western Province of Rwanda. Sebeya catchment is one of the most affected areas by soil erosion hazards causing loss of crops due to the destruction of agricultural plots or riverbanks, river sedimentation and damages to the existing water treatment and hydropower plants in the downstream part of the river. The aims of this research were to assess the performance of erosion remediation measures and to propose the Best Management Practices (BMPs) for erosion control in Sebeya catchment. Using literature review, site visits, questionnaire and interviews, various erosion control measures were analyzed in terms of performance and suitability. Land slope and soil depth maps were generated using ArcGIS software. The interview results indicated that among the 22 existing soil erosion control measures, about 4.57% of farmers confirmed their existence while 95.43% expressed the need of their implementation in Sebeya catchment. Furthermore, economic constraints were found to be the main limitative factors against the implementation of soil erosion control measures in Sebeya catchment. Also, the majority of farmers suggest trainings and mobilization of a specialized technical team to assist them in implementing soil conservation measures and to generalize the application of fertilizers in the whole catchment. Finally, soil erosion control measures including agro-forestry, terraces, mulching, tree planting, contour bunds, vegetative measures for slopes and buffer zones, check dams, riverbanks stabilization were proposed and recommended to be implemented in Sebeya catchment. Keywords: Erosion control measures, Sebeya catchment, Rwanda

scholarly journals Evaluating Hybrid Bermudagrass Using Spectral Reflectance under Different Mowing Heights and Trinexapac-ethyl Applications

2017 ◽  
Vol 27 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Dana Sullivan ◽  
Jing Zhang ◽  
Alexander R. Kowalewski ◽  
Jason B. Peake ◽  
William F. Anderson ◽  
...  
Keyword(s):  
Spectral Reflectance ◽  
Management Practices ◽  
Cynodon Dactylon ◽  
Functional Performance ◽  
Lignin Content ◽  
Vegetation Indices ◽  
Variety Trials ◽  
Fiber Analysis ◽  
Green Cover ◽  
Aesthetic Performance

Quantitative spectral reflectance data have the potential to improve the evaluation of turfgrasses in variety trials when management practices are factors in the testing of turf aesthetics and functionality. However, the practical application of this methodology has not been well developed. The objectives of this research were 1) to establish a relationship between spectral reflectance and turfgrass quality (TQ) and percent green cover (PGC) using selected reference plots; 2) to compare aesthetic performance (TQ, PGC, and vegetation indices) and functional performance (surface firmness); and 3) to evaluate lignin content as an alternate means to predict surface firmness in turfgrass variety trials of hybrid bermudagrass [Cynodon dactylon × C. transvaalensis]. A field study was conducted on mature stands of three varieties (‘TifTuf’, ‘TifSport’, and ‘Tifway’) and two experimental lines (04-47 and 04-76) at two mowing heights (0.5 and 1.5 inch) and trinexapac-ethyl application (0.15 kg·ha−1 and nontreated control) treatments. Aesthetic performance was estimated by vegetation indices, spectral reflectance, visual TQ, and PGC. The functional performance of each variety/line was measured through surface firmness and fiber analysis. Regression analyses were similar when using only reference plots or all the plots to determine the relationship between individual aesthetic characteristics. Experimental line 04-47 had lower density in Apr. 2010, whereas varieties ‘TifTuf’, ‘TifSport’, and ‘Tifway’ were in the top statistical group for aesthetic performance when differences were found. ‘TifSport’ and ‘Tifway’ produced the firmest surfaces, followed by ‘TifTuf’, and finally 04-76 and 04-47, which provided the least firm surface. Results of leaf fiber analysis were not correlated with turf surface firmness. This study indicates that incorporating quantitative measures of spectral reflectance could reduce time and improve precision of data collection as long as reference plots with adequate range of green cover are present in the trials.

scholarly journals Directed evolution of Metarhizium fungus improves its biocontrol efficacy against Varroa mites in honey bee colonies

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jennifer O. Han ◽  
Nicholas L. Naeger ◽  
Brandon K. Hopkins ◽  
David Sumerlin ◽  
Paul E. Stamets ◽  
...  
Keyword(s):  
Directed Evolution ◽  
Honey Bee ◽  
Entomopathogenic Fungi ◽  
Management Practices ◽  
Abiotic Factors ◽  
Control Measures ◽  
Residual Effects ◽  
Effective Control ◽  
Great Promise ◽  
Bee Colonies

AbstractEntomopathogenic fungi show great promise as pesticides in terms of their relatively high target specificity, low non-target toxicity, and low residual effects in agricultural fields and the environment. However, they also frequently have characteristics that limit their use, especially concerning tolerances to temperature, ultraviolet radiation, or other abiotic factors. The devastating ectoparasite of honey bees, Varroa destructor, is susceptible to entomopathogenic fungi, but the relatively warm temperatures inside honey bee hives have prevented these fungi from becoming effective control measures. Using a combination of traditional selection and directed evolution techniques developed for this system, new strains of Metarhizium brunneum were created that survived, germinated, and grew better at bee hive temperatures (35 °C). Field tests with full-sized honey bee colonies confirmed that the new strain JH1078 is more virulent against Varroa mites and controls the pest comparable to current treatments. These results indicate that entomopathogenic fungi are evolutionarily labile and capable of playing a larger role in modern pest management practices.

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