Thesis(M.Sc.(Plant Protection))-- University of Limpopo,2019 / Previously, cucurbitacin-containing phytonematicides that were drench-applied in
black plastic containers filled with pasteurised loam soil when placed on the soil
surface had no effect on suppression of population densities of root-knot
(Meloidogyne species) nematodes. The active ingredients of cucurbitacin-containing
phytonematicides, namely, the cucurbitacins, had been shown to be thermophilic,
with the failure of the products explained from the view of the variability induced by
container-type and aboveground positioning. The view was investigated further using
Nemarioc-AL and Nemafric-BL phytonematicides as influenced by container-type
and positioning on growth of tomato (Solanum lycopersicum L.) plants and
suppression of M. incognita population densities. Tomato cv. ′Floradade′ seedlings
were transplanted into 30-cm-diameter brown pot belowground, brown pot
aboveground, black pot belowground, black pot aboveground, 5 L polyethylene
plastic bag belowground and 5 L polyethylene plastic bag aboveground, each
containing 5-dm3 steam-pasteurised sandy loam soil amended with Hygromix at 3:1
(v/v) ratio. Seedlings were inoculated with 2000 eggs and second-stage juveniles
(J2) of M. incognita race 2, with Nemarioc-AL and Nemafric-BL phytonematicides
applied once 17 days after inoculation in both Experiment 1 and Experiment 2. Also,
standard cultural practices were applied throughout the trial. At 56 days after
inoculation, container-type and positioning had significant effects on various plant
growth and essential nutrient element variables in Experiment 1 and Experiment 2,
except that the six treatments did not have significant effects on nutrient elements
and nematode population densities in Experiment 2. Relative to brown plastic pot
belowground, treatments either increased or decreased plant growth, essential
nutrient elements and nematode densities in Experiment 1, with selective similaritiesin Experiment 2. Specifically, nematode variables except for J2 in soil and total
nematode population densities were significantly affected by the treatments in
Experiment 2. Relative to the standard, plastic bag belowground increased J2 in soil
and total population in soil by 18%. In conclusion, both container-type and
positioning had effects on the efficacy of phytonematicides on plant growth,
accumulation of essential nutrient elements and suppression of nematode population
densities. Consequently, in trials where cucurbitacin-containing phytonematicides
are conducted in microplots, brown plastic pots with the belowground positioning
should be used to enhance the efficacy of the phytonematicides in stimulating plant
growth and suppression of nematode population densities.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ul/oai:ulspace.ul.ac.za:10386/3156 |
| Date | January 2019 |
| Creators | Makwapana, Tshepho |
| Contributors | Mafeo, T. P., Mashela, P.W |
| Publisher | University of Limpopo |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | xxii,80 leaves |
| Relation |
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