Thesis (M.A. Agricultural Management (Plant Production)) -- University of Limpopo, 2017 / Nemafric-BL and Nemarioc-AL phytonematicides, which are being researched
and developed to serve as alternatives to methyl bromide, have not been tested
against plant growth and accumulation of essential nutrient elements in
watermelon (Citrullus lanatus) cultivars. The objectives of this study were two
fold, to determine the (1) overall growth responses and accumulation of selected
essential nutrient elements in watermelon cultivars ‘Congo’ and ‘Charleston Gray’
and suppression of Meloidogyne javanica in response to increasing
concentrations of Nemafric-BL and Nemarioc-AL phytonematicides, and (2)
efficacy of Velum, Nemafric-BL and Nemarioc-AL phytonematicides on growth of
watermelon, accumulation of selected essential nutrient elements in leaf tissues
of cv. ‘Congo’ and the suppression of population densities of Meloidogyne
species. Objective 1 and Objective 2 were achieved under greenhouse and field
conditions, respectively. At 56 and 90 days after initiating the greenhouse and
field treatments, respectively, the data were collected and subjected to statistical
analyses. Nemafric-BL phytonematicide significantly affected growth of
watermelon cultivars ‘Charleston Gray’ and ‘Congo’, whereas Nemarioc-AL
phytonematicide did not have any significant effects on the plant variables of both
cultivars. Generally, plant growth variables and increasing concentrations of
Nemafric-BL phytonematicide had density-dependent growth (DDG) patterns,
which were quantified through either positive or quadratic equations (Chapter 3).
In contrast, both phytonematicides had significant effects on selected nutrient
elements in leaf tissues of both watermelon cultivars. The affected nutrient
elements, P, Mn and Na versus increasing concentrations of phytonematicides
exhibited the DDG patterns, which were also quantified through either positive or
quadratic equations (Chapter 3). The phytonematicides were consistent in
suppressing nematode numbers in both watermelon cultivars. Comparison of
synthetic nematicide Velum and the two phytonematicides under field conditions
suggested that, relative to untreated control, the three products each stimulated
growth of watermelon cv. ‘Congo’. The efficacy of Nemafric-BL and Nemarioc-AL
phytonematicides on suppression of population densities of Meloidogyne species
was comparable to that of Velum. In conclusion, Nemafric-BL and Nemarioc-BL
phytonematicides were highly effective in managing population densities of
Meloidogyne species in watermelon cultivars and also affected the partitioning of
selected nutrient elements in tissues. The study provided essential information
that could assist in decision-making in nematode management in watermelon
production, particularly in fertiliser application.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ul/oai:ulspace.ul.ac.za:10386/4176 |
| Date | January 2017 |
| Creators | Nhlane, Ramadimetja Norriah |
| Contributors | Pofu, K. M., Mashela, P. W. |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | xxvi, 96 leaves |
| Relation |
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