Biological control of head rot and damping-off of sunflower using yeasts, Bacillus spp. and Trichoderma spp.

Masters Degree. University of KwaZulu-Natal, Pietermaritzburg.The soil-borne fungi Sclerotinia sclerotiorum, Sclerotium rolfsii and Rhizoctonia solani are ubiquitous plant pathogens with a wide host range. They are among the most widespread pathogens, and cause destructive diseases of many crops, including sunflower (Helianthus annus L.), an economically important oilseed crop. Chemical fungicides are available for control of seedling damping-off caused by these pathogens, but there are environmental concerns and the possibility of developing tolerance in pathogen populations, which have led to a drastic reduction in their usage and increased the pressure to find alternative means of disease control. Additionally, there are no registered fungicides that effectively control Sclerotinia head rot of sunflower caused by S. sclerotiorum in South Africa. Successes in biological control (biocontrol) and plant growth promotion research have led to the development of various Trichoderma and Bacillus products, which are available commercially. This study was conducted to evaluate the effect of three strains of Bacillus spp., one yeast and one commercial strain of Trichoderma spp., and their respective combinations, on Sclerotinia head rot on sunflower. An additional commercial strain of Trichoderma spp. was also evaluated for the control of damping-off. In vitro biological control and growth promotion studies were carried out under greenhouse conditions with the use of foliar spray treatment as the method of application for head rot, and seed and soil drench treatments for damping-off. In vitro screening was undertaken to select the best Bacillus and yeast isolates from 136 Bacillus spp. and 100 yeasts isolated from local wild sunflower heads. Dual-culture bioassays were undertaken and isolates were assessed for antagonism by examining the radial growth of S. sclerotiorum mycelium. A scale was used to group the isolates, based on their inhibition ability in order to select the best isolates to screen in vivo. Seventeen Bacillus isolates achieved a Class 3 rating (≥70% inhibition of pathogen mycelial growth), while only 4 yeast isolates achieved a Class 2 rating (41-69% inhibition). The isolates, along with T. atroviride strain 77 (T77), were further screened in vivo under greenhouse conditions for antagonistic activity against Sclerotinia head rot of sunflower cv. PAN7080 plants, when plants were at the R6 reproductive stage. Disease incidence was recorded 14 days after inoculation with BCAs and S. sclerotiorum, and grain was harvested, dried and weighed 85-115 days after planting. A total of 20 yeast and Bacillus isolates were screened against S. sclerotiorum and 4 Bacillus isolates and 1 yeast isolate reduced disease incidence by ≥50%, compared to the disease control. Bacillus B16 resulted in complete disease suppression, followed by B24, B26 and T77, which reduced disease incidence to 12.5%. Seven of the 20 yeast and Bacillus isolates, along with T77, significantly improved grain yield. B16 resulted in the highest grain yield, followed by T77. The effect of inoculum concentration was evaluated for the best performing yeast and Bacillus spp. isolates. A concentration of 1 x 108 cells mL-1 for yeast Y79, and 1 x 109 cfu mL-1 for B16, B24 and B26 caused the greatest disease suppression and improvement in grain yield. In comparison to the Bacillus isolates, Y79 was the poorest performing biocontrol agent (BCA), reducing the incidence of head rot the least. In addition, it was not as effective at improving grain yield and failed to perform consistently between the first, second and third greenhouse screening. Sunflower heads treated with single and combined inoculations of T77, Y79 and B16, B24 and B26 exhibited improved grain yield. Combined inoculations of B16 + B26 and B26 + B24 provided over 10.0% increase in grain yield (12.8% and 15.5%, respectively) over the disease-free control. Y79, when inoculated in combination with B16 and B24, scored reduced disease incidences of 62.5% and 37.5% as well as improved grain yields of 15.8 g and 36.0 g, respectively. In vitro dual-culture assays carried out with T. asperellum strain kd (Tkd) showed effective antibiosis activity and marked mycoparasitism of S. sclerotiorum, R. solani and S. rolfsii, despite the BCA performing poorly according to the Bell rating scale in dual culture plates. Greenhouse trials were carried out in Speedling 24® trays, and Tkd was applied as a seed treatment alone and/or a monthly-bimonthly soil drench. Various other greenhouse trials were set up to evaluate the potential of Tkd to suppress damping-off of sunflower caused by the three pathogens, and several growth parameters were measured. Seed treatment in combination with a monthly or bimonthly soil drench significantly increased seedling, shoot, root and head dry weight, along with root area, when tested against all three pathogens- effectively reducing disease incidence. Reduced disease incidence and enhanced seedling and plant growth were also achieved when Tkd was applied as a seed treatment alone, drench at planting alone, and drench at planting + bimonthly drench, but at lower levels. A number of methods were adapted from studies carried out in other parts of the world with the objective of finding a fast and reliable method of inducing sclerotia of S. sclerotiorum to germinate carpogenically and produce ascospores. However, none of the published techniques worked under the conditions tested. Only one method, adapted from a study conducted by a fellow South African researcher, resulted in stipe formation, but not in ascospore production. The failure of these published techniques to work under the local conditions may be attributed to the fungus having stringent requirements for environmental conditioning before it will sporulate carpogenically. It appears that these requirements vary with the geographic source of the sclerotia, and that effective conditioning parameters in one place may not work in other geographic locations. The results presented in this dissertation confirm the concept of biological control by Trichoderma spp. and Bacillus spp. as a viable disease control strategy to manage S. sclerotiorum of sunflower. Furthermore, this dissertation forms a basis for further Trichoderma-Bacillus-Yeast interaction studies to determine whether strains of these three organisms could be combined to enhance biocontrol and plant growth promotion

Has the UK Healthy Start voucher scheme been associated with an increased fruit and vegetable intake among target families? Analysis of Health Survey for England data, 2001–2014

Background: Healthy Start (HS) is a UK government programme, introduced in 2006, providing vouchers to pregnant women or families with children aged <4 who are in receipt of certain benefits. Vouchers can be exchanged for fruit and vegetables (F&V), milk or infant formula. We sought to identify any association between HS and F&V intake. Methods: We analysed repeated cross-sectional data from the Health Survey for England. Study participants were classified into one of four groups: one HS-eligible group and three control groups, meeting only the income or demographic or no eligibility criterion. Outcome measures were mean F&V intake and the proportions of participants consuming ≥3 and ≥1 portion/day. Outcomes were compared across the four groups over four time periods: 2001–2003, 2004–2006, 2007–2009 and 2010–2014. Regression analyses examined whether F&V intake among HS-eligible participants had a significantly different rate of change from those in the control groups. Results: The change in mean F&V consumption over time was similar in HS-eligible adults and children to that of the control groups. Likewise, the change in odds of consuming ≥3 or ≥1 portion of F&V/day over time was similar among HS-eligible participants and control groups. Conclusion: This study found that during the period 2001–2003 to 2010–2014, F&V consumption among adults and children in households deemed eligible for HS changed similarly to that of other adults and children. Potential explanations include that vouchers may have been spent on milk or infant formula, or that vouchers helped protect F&V consumption in low-income households

Does the use of prediction equations to correct self-reported height and weight improve obesity prevalence estimates? A pooled cross-sectional analysis of Health Survey for England data.

OBJECTIVE: Adults typically overestimate height and underestimate weight compared with directly measured values, and such misreporting varies by sociodemographic and health-related factors. Using self-reported and interviewer-measured height and weight, collected from the same participants, we aimed to develop a set of prediction equations to correct bias in self-reported height and weight and assess whether this adjustment improved the accuracy of obesity prevalence estimates relative to those based only on self-report. DESIGN: Population-based cross-sectional study. PARTICIPANTS: 38 940 participants aged 16+ (Health Survey for England 2011-2016) with non-missing self-reported and interviewer-measured height and weight. MAIN OUTCOME MEASURES: Comparisons between self-reported, interviewer-measured (gold standard) and corrected (based on prediction equations) body mass index (BMI: kg/m2) including (1) difference between means and obesity prevalence and (2) measures of agreement for BMI classification. RESULTS: On average, men overestimated height more than women (1.6 cm and 1.0 cm, respectively; p<0.001), while women underestimated weight more than men (2.1 kg and 1.5 kg, respectively; p<0.001). Underestimation of BMI was slightly larger for women than for men (1.1 kg/m2 and 1.0 kg/m2, respectively; p<0.001). Obesity prevalence based on BMI from self-report was 6.8 and 6.0 percentage points (pp) lower than that estimated using measured BMI for men and women, respectively. Corrected BMI (based on models containing all significant predictors of misreporting of height and weight) lowered underestimation of obesity to 0.8pp in both sexes and improved the sensitivity of obesity over self-reported BMI by 15.0pp for men and 12.2pp for women. Results based on simpler models using age alone as a predictor of misreporting were similar. CONCLUSIONS: Compared with self-reported data, applying prediction equations improved the accuracy of obesity prevalence estimates and increased sensitivity of being classified as obese. Including additional sociodemographic variables did not improve obesity classification enough to justify the added complexity of including them in prediction equations

Establishing the international prevalence of self-reported child maltreatment: a systematic review by maltreatment type and gender

Background Estimating the prevalence of child maltreatment is challenging due to the absence of a clear ‘gold standard’ as to what constitutes maltreatment. This systematic review aims to review studies using self-report maltreatment to capture prevalence rates worldwide. Methods PubMed, Ovid SP and grey literature from the NSPCC, UNICEF, The UK Government, and WHO from 2000 to 2017 were searched. The literature review focused on the variation found in self-reported lifetime prevalence for each type of maltreatment between studies by continent and gender, and how methodological differences may explain differences found. Results Sexual abuse is the most commonly studied form of maltreatment across the world with median (25th to 75th centile) prevalence of 20.4% (13.2% to 33.6%) and 28.8% (17.0% to 40.2%) in North American and Australian girls respectively, with lower rates generally for boys. Rates of physical abuse were more similar across genders apart from in Europe, which were 12.0% (6.9% to 23.0%) and 27.0% (7.0% to 43.0%) for girls and boys respectively, and often very high in some continents, for example, 50.8% (36.0% to 73.8%) and 60.2% (43.0% to 84.9%) for girls and boys respectively in Africa. Median rates of emotional abuse were nearly double for girls than boys in North America (28.4% vs 13.8% respectively) and Europe (12.9% vs 6.2% respectively) but more similar across genders groups elsewhere. Median rates of neglect were highest in Africa (girls: 41.8%, boys: 39.1%) and South America (girls: 54.8%, boys: 56.7%) but were based on few studies in total, whereas in the two continents with the highest number of studies, median rates differed between girls (40.5%) and boys (16.6%) in North America but were similar in Asia (girls: 26.3%, boys: 23.8%). Conclusions Median prevalence rates differ substantially by maltreatment category, gender and by continent. The number of studies and available data also varies and relatively little is known about prevalence for some forms of maltreatment, particularly outside of the North American context. Prevalence rates require caution in interpretation as some variation will reflect methodological differences, including the data collection methods, and how the maltreatment is defined

Scoring the ICECAP-A capability instrument. Estimation of a UK general population tariff

This paper reports the results of a best–worst scaling (BWS) study to value the Investigating Choice Experiments Capability Measure for Adults (ICECAP-A), a new capability measure among adults, in a UK setting. A main effects plan plus its foldover was used to estimate weights for each of the four levels of all five attributes. The BWS study was administered to 413 randomly sampled individuals, together with sociodemographic and other questions. Scale-adjusted latent class analyses identified two preference and two (variance) scale classes. Ability to characterize preference and scale heterogene-ity was limited, but data quality was good, and the final model exhibited a high pseudo-r-squared. After adjusting for heterogeneity, a population tariff was estimated. This showed that ‘attachment ’ and ‘stability ’ each account for around 22 % of the space, and ‘autonomy’, ‘achievement ’ and ‘enjoyment ’ account for around 18 % each. Across all attributes, greater value was placed on the difference between the lowest levels of capability than between the highest. This tariff will enable ICECAP-A to be used in economic evaluation both within the field of health and across public policy generally. © 2013 The Authors. Health Economics published by John Wiley &amp; Sons Ltd

Ungrading General Education: Preliminary Results from a Pilot Study

A group of faculty members representing more than 20 courses listed in the Eastern Kentucky University General Education curriculum participated in a pilot program to test and measure the effectiveness of “ungraded” pedagogy. “Ungrading,” as defined by the group, can be any conscious effort to move student emphasis away from grades and onto learning. Given this definition, ungrading took many forms in the pilot: gradeless classrooms, grading contracts, and greater choice of assignments by students, to name a few. At the end of the semester, quantitative and qualitative data was gathered from student course evaluations; DFW and retention rates were considered; and focus groups comprised of students in ungraded classes were convened. This piece provides preliminary results from the pilot and in an effort to begin a larger conversation about the widespread adoption of ungraded pedagogies

Tracing the Filamentary Structure of the Galaxy Distribution at z~0.8

We study filamentary structure in the galaxy distribution at z ~ 0.8 using data from the Deep Extragalactic Evolutionary Probe 2 (DEEP2) Redshift Survey and its evolution to z ~ 0.1 using data from the Sloan Digital Sky Survey (SDSS). We trace individual filaments for both surveys using the Smoothed Hessian Major Axis Filament Finder, an algorithm which employs the Hessian matrix of the galaxy density field to trace the filamentary structures in the distribution of galaxies. We extract 33 subsamples from the SDSS data with a geometry similar to that of DEEP2. We find that the filament length distribution has not significantly changed since z ~ 0.8, as predicted in a previous study using a \LamdaCDM cosmological N-body simulation. However, the filament width distribution, which is sensitive to the non-linear growth of structure, broadens and shifts to smaller widths for smoothing length scales of 5-10 Mpc/h from z ~ 0.8 to z ~ 0.1, in accord with N-body simulations.Comment: 10 pages, 8 figures, accepted for the publication in MNRA

Scoring the ICECAP - a capability instrument : estimation of a UK general population tariff

This paper reports the results of a best–worst scaling (BWS) study to value the Investigating Choice Experiments Capability Measure for Adults (ICECAP-A), a new capability measure among adults, in a UK setting. A main effects plan plus its foldover was used to estimate weights for each of the four levels of all five attributes. The BWS study was administered to 413 randomly sampled individuals, together with sociodemographic and other questions. Scale-adjusted latent class analyses identified two preference and two (variance) scale classes. Ability to characterize preference and scale heterogeneity was limited, but data quality was good, and the final model exhibited a high pseudo-r-squared. After adjusting for heterogeneity, a population tariff was estimated. This showed that ‘attachment’ and ‘stability’ each account for around 22% of the space, and ‘autonomy’, ‘achievement’ and ‘enjoyment’ account for around 18% each. Across all attributes, greater value was placed on the difference between the lowest levels of capability than between the highest. This tariff will enable ICECAP-A to be used in economic evaluation both within the field of health and across public policy generally. © 2013 The Authors. Health Economics published by John Wiley & Sons Ltd