ORCID Profile
0000-0003-4371-5519
Current Organisation
University of the South Pacific
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Publisher: Springer Science and Business Media LLC
Date: 17-11-2014
Publisher: Unpublished
Date: 2019
Publisher: CSIRO Publishing
Date: 2008
DOI: 10.1071/SP08014
Publisher: CSIRO Publishing
Date: 2007
DOI: 10.1071/SP07013
Abstract: Six tomato cultivars Moneymaker, Beefsteak, Roma, Summertaste, Mini Roma and Smallfry were tested for their susceptibility to root- knot nematodes at inoculum levels of 200, 400, 600 Juveniles (J2) per pot. All were found to be susceptible to varying degrees as egg masses were present in all with Moneymaker and Roma being the most susceptible and Mini Roma, the least susceptible. The inoculum levels had a significant effect (p .05) on the number of galls and plant weights. The gall numbers and plant weights was negatively correlated, with the highest gall numbers and lowest plant weights recorded at the highest inoculum level in all cultivars except in Mini Roma in which there was little variation in gall numbers and plant weights.
Publisher: Wiley
Date: 14-09-2013
DOI: 10.1111/AAB.12065
Publisher: CSIRO Publishing
Date: 2008
DOI: 10.1071/SP08005
Publisher: Springer Science and Business Media LLC
Date: 27-08-2015
Publisher: Edith Cowan University
Date: 06-2021
DOI: 10.14221/AJTE.2021V46N6.2
Abstract: The purpose of this study was to determine the extent to which teachers perceive their principal to be effectively exhibiting an instructional leadership role. Data for the study were collected from teachers (N=24) in a rural secondary school in Fiji using the Principal Instructional Management Rating Scale (PIMRS) developed and advocated by Hallinger (1990). In addition to Likert scale items, the questionnaire included open-ended questions to gain deeper insights into teachers’ ratings of each item. Analyses of the data revealed that ratings for the principal were the highest for communicating school goals to students and protecting instructional time while supervision and evaluation of instruction were the lowest-rated items. The lack of professional preparation for an instructional leadership role and the dual role of the rural principal as school leader and teacher, which appears to compromise both roles, may together explain the scant attention paid to the instructional leadership role. These findings have implications for principals’ workload and in turn instructional leadership practices, which the Fiji Ministry of Education could re-visit to avoid compromising either the leadership or teaching role.
Publisher: Unpublished
Date: 2009
Publisher: Cambridge University Press (CUP)
Date: 12-2010
Abstract: Weeds can act as reservoir hosts of a range of pests and diseases. Information and knowledge on the host status of weeds to common pests and diseases can be used to develop integrated weed and pest management strategies. As part of a survey on the distribution and ersity of root-knot nematodes on crops in Fiji, the root-knot nematode host status of weeds was also studied. Weeds growing in root-knot nematode infested farms ( n = 189) and bioassay pot soil s les ( n = 277) were identified, and their host status was determined on the basis of a root gall and egg-mass index scale from 0 to 5. A total of 45 weed species were recorded as potential weed hosts of root-knot nematodes with a gall index from 1 to 5. Using the weed and tomato bioassay method, a total of 11 nonhost weed species were recorded with a gall index of 0, relative to infected tomato growing in pot soil s les. Common weeds infected by root-knot nematodes on farms and in bioassay pot soil included slender amaranth, old world diamond-flower, tropic ageratum, sicklepod, mimbra, balsamapple, purple bushbean, little ironweed, ivy gourd, and cutleaf groundcherry. The presence of egg masses on the weed hosts indicated their ability to sustain root-knot nematode populations and, thus, their potential to act as reservoir hosts.
Publisher: Unpublished
Date: 2018
Publisher: Wiley
Date: 20-10-2021
DOI: 10.1111/AAB.12739
Abstract: The plant‐parasitic nematodes (PPNs), Heterodera zeae , Hirschmanniella oryzae and Meloidogyne graminicola , are economically important pests of major grain crops. Each of these species is still absent from the majority of countries, so there is great concern about their spread. However, the areas particularly at risk of invasion and the potential global distributions of these nematode pests are yet to be identified. This paper identifies these areas, together with the main factors that could facilitate establishment in new areas using CLIMEX models. Parameterised using published studies of species phenology and global species distributions, the models correctly identified the areas invaded recently by M. graminicola and H. zeae . The vast majority of the areas of the world under wheat, rice and maize were identified as suitable for the nematodes. The nematodes are not yet established in many of these areas, suggesting that biosecurity measures may be particularly warranted to prevent the spread of these species to the new suitable areas identified. Intensive cropping systems under irrigation were identified as being at much greater risk than rain‐fed cropping systems. The potential detrimental effects from introduction and local spread of PPNs in irrigation water could undermine suggested potential gains from using irrigation to increase world food production and meet increasing demand. These results mean that biosecurity measures for PPNs are justified.
Publisher: Springer Science and Business Media LLC
Date: 27-04-2012
Publisher: Pensoft Publishers
Date: 13-09-2013
Publisher: Wiley
Date: 16-07-2013
DOI: 10.1111/EPP.12050
Publisher: Scientific Societies
Date: 06-2012
Abstract: Rates and modes of dispersal of potato cyst nematodes (PCNs) were investigated. Analysis of records from eight countries suggested that PCNs spread a mean distance of 5.3 km/year radially from the site of first detection, and spread 212 km over ≈40 years before detection. Data from four countries with more detailed histories of invasion were analyzed further, using distance from first detection, distance from previous detection, distance from nearest detection, straight line distance, and road distance. Linear distance from first detection was significantly related to the time since the first detection. Estimated rate of spread was 5.7 km/year, and did not differ statistically between countries. Time between the first detection and estimated introduction date varied between 0 and 20 years, and differed among countries. Road distances from nearest and first detection were statistically significantly related to time, and gave slightly higher estimates for rate of spread of 6.0 and 7.9 km/year, respectively. These results indicate that the original site of introduction of PCNs may act as a source for subsequent spread and that this may occur at a relatively constant rate over time regardless of whether this distance is measured by road or by a straight line. The implications of this constant radial rate of dispersal for biosecurity and pest management are discussed, along with the effects of control strategies.
Publisher: Wiley
Date: 06-2022
DOI: 10.1002/ECE3.8997
Abstract: Entomopathogenic nematode (EPN) Heterorhabditis indica is a promising biocontrol candidate. Despite the acknowledged importance of EPN in pest control, no extensive data sets or maps have been developed on their distribution at global level. This study is the first attempt to generate Ecological Niche Models (ENM) for H . indica and its global Habitat Suitability Map (HSM) for H. indica to generate biogeographical information and predicts its global geographical range and help identify of prospective areas for its exploration and to help identify the suitable release areas for biocontrol purpose. The aim of the modeling exercise was to access the influence of temperature and soil moisture on the biogeographical patterns of H . indica at the global level. Global Heterorhabditis indica ecosystems. CLIMEX software was used to model the distribution of H . indica and assess the influence of environmental variable on its global distribution. In total, 162 records of H . indica occurrence from 27 countries over 25 years were combined to generate the known distribution data. The model was further fine‐tuned using the direct experimental observations of the H . indica's growth response to temperature and soil moisture. Model predicts that much of the tropics and subtropics have suitable climatic conditions for H . indica . It further predicts that H . indica distribution can extend into warmer temperate climates. Examination of the model output, predictions maps at a global level indicate that H . indica distribution may be limited by cold stress, heat stress, and dry stresses in different areas. However, cold stress appears to be the major limiting factor. This study highlighted an efficient way to construct HSM for EPN potentially useful in the search/release of target species in new locations. The study showed that H . indica which is known as warm adapted EPN generally found in tropics and subtropics can potentially establish itself in warmer temperate climates as well. The model can also be used to decide the release timing of EPN by adjusting with season for maximum growth. The model developed in this study clearly identified the value and potential of Habitat Suitability Map (HSM) in planning of future surveys and application of H . indica .
No related grants have been discovered for Sunil Singh.