Thesis (M. A. Agriculture (Plant Protection)) -- University of Limpopo, 2019 / The successful cultivation of nightshade (Solanum retroflexum) as a leafy vegetable with the nutritional potential of contributing to food security in marginalised communities of Limpopo Province could be limited by high population densities of root-knot (Meloidogyne species) nematodes. However, the use of Nemarioc-AL/AG and Nemafric-BL/BG phytonematicides in suppressing nematodes and not being phytotoxic requires the empirically-developed non-phytotoxic concentration, technically referred to as Mean Concentration Stimulation Point (MCSP). The MCSP, developed using the Curve-fitting Allelochemical Response Data (CARD) computer-based model, is crop-specific, hence it should be developed for every crop. The objective of this study was to investigate the influence of Nemarioc-AL/AG and Nemafric-BL/BG phytonematicides on growth of nightshade, accumulation of essential nutrient elements and cucurbitacin residues in nightshade leaves. Microplots were established by inserting 20-cm-diameter plastic pots into 10-cm-deep holes at 0.6 m intra-row and 0.6 m inter-row spacing. Each pot was filled with 10 000 cm3 steam-pasteurised river sand and Hygromix at 3:1. After establishment, Nemarioc-AL and Nemafric-BL phytonematicides were applied at 7-day interval, whereas, Nemarioc-AG and Nemafric-BG phytonematicides were only applied at planting. Two separate experiments for Nemarioc-AL and Nemafric-BL phytonematicides were conducted in summer (November-January) 2017/2018 under microplot conditions with each comprising treatments namely; 0, 2, 4, 8, 16, 32 and 64%, similarly, two separate experiments for the following phytonematicides, Nemarioc-AG and Nemafric-BG comprised treatments namely; 0, 2, 4, 6, 8, 10 and 12 g arranged in a randomised complete block design (RCBD), with 12 replications. The nutrient elements in leaf tissues of nightshade were analysed using the inductively coupled plasma optical emission spectrometry (ICPE-9000) while, cucurbitacin A and B were xii each quantified using the isocratic elution Shimadzu HPLC Prominence with Shimadzu CTO-20A diode array detector. Plant growth and nutrient elements variables were subjected to the CARD computer-based model to generate biological indices to generate the curves, quadratic equations and the related biological indices (Dm, Rh, k) (Liu et al., 2003). The MCSP values were calculated using the biological indices of plant or nutrient element variables which, along with increasing concentration of Nemarioc-AL, Nemafric BL, Nemarioc-AG and Nemafric-BG phytonematicides, exhibited positive quadratic relations, with R2 ≥ 25. Using cucurbitacin A and B standards, residues of Nemarioc AL/AG and Nemafric-BL/BG phytonematicides, were not detected in nightshade leaves, respectively. Dry root mass and dry shoot mass of nightshade over increasing concentration of Nemarioc-AL phytonematicide each exhibited a quadratic relationship, with the models explained by 93 and 61%, respectively. Dry root mass, dry shoot mass, plant height, chlorophyll content and stem diameter against increasing concentration of Nemafric-BL phytonematicide each exhibited positive quadratic relationships with the models explained by 95, 72, 65, 78 and 62%, respectively. Plant height, stem diameter and dry root mass against increasing concentration of Nemarioc-AG phytonematicide each exhibited positive quadratic relationships with their models explained by 93, 88 and 91%, respectively. Dry shoot mass and stem diameter against increasing concentration of Nemafric-BG phytonematicide each exhibited positive quadratic relationships with their models explained by 94 and 84%, respectively. Na, Fe and K over increasing concentration of Nemarioc-AL phytonematicide each exhibited positive quadratic relationships with their associations explained by 96, 91 and 95%, respectively. Zn over increasing concentration of Nemafric-BL phytonematicide exhibited positive quadratic relationship with the model explained by 98%. Fe over increasing concentration of Nemarioc-AG phytonematicide exhibited positive quadratic xiii relationship with the association explained by 91%. Fe, Na, K and Zn over increasing concentration of Nemafric-BG phytonematicide each exhibited positive quadratic relationships with their associations explained by 81, 90, 80 and 89%, respectively, whereas, on the contrary, Zn over increasing concentration of Nemarioc-AG phytonematicide exhibited negative quadratic relationship with the association explained by 96%. Significant (P ≤ 0.05) plant variables were subjected to CARD, to generate biological indices which were used to compute the MCSP using the relation: MCSP = Dm + Rh/2 and the overall sensitivity value (∑k). In Nemarioc-AL phytonematicide trial, MCSP = 3.02% and ∑k = 1 for plant variables, whereas, MCSP and ∑k for nutrient elements were 12.09% and 1, respectively. In Nemafric-BL phytonematicide trial, MCSP = 3.08% and ∑k = 0 for plant variables, while MCSP = 2484.14% and ∑k = 0 for nutrient elements. In Nemarioc-AG phytonematicide trial, MCSP = 3.47 g and ∑k = 0 for plant variables, whereas, for nutrient elements MCSP = 8.49 g and ∑k = 1. In Nemafric-BG phytonematicide trial, MCSP = 4.70 g and ∑k = 0 for plant variables, whereas, MCSP =723.75 g and ∑k = 1 for nutrient elements. In conclusion, the application of Nemarioc-AL/AG and Nemafric-BL/BG phytonematicides had the ability to stimulate the growth of nightshade and enhance the accumulation of the selected nutrient elements without leaving cucurbitacin chemical residues in leaf tissues of nightshade. / National Research Foundation (NRF) and the Land Bank Chair of Agriculture

Toxocara canis (Werner, 1782) is the round worm most frequently found in dogs. From surveys in the United States, approximately 40-100% of young dogs and 5-70% of older dogs are infected with this parasite. Of 97 adult dogs surveyed in Provo, Utah, in 1968, 17. 5% were infected with T. canis (Fox, personal communication). Adult dogs become infected by ingesting food contaminated with the infective eggs from this parasite. Puppies are most frequently infected prenatally from their mother (Nifontov, I 949; Yutuc, 1949; Sprent, 1958; Webster, I 958; Douglas and Baker, 1959; Scothorn, Koutz and Groves, 1965; Wiseman. 19 69).

Considerable research has been done on the influence of various chemical adjuvants, such as glycerol and dimethyl sulfoxide (DMSO) on the survival of protozoan organisms. (Levine and Marquardt, 1955; Levine, Mizell and Houlahan, 1958; Levine, et al. 1962; Levine and Andersen, 1965, 1966; Fitzgerald and Levine 1957 1 1961; Diamond, 1964). Considerably less work has been done on metazoan parasites. The effects of various chemical adjuvants on the survival of Haemonchus contortus, the large stomach worm of sheep, at extremely low temperatures has not been reported. The purpose of this research was to determine if different concentrations of chemical adjuvants influence the survival of the free-living stages of H. contortus at temperatures ranging from 4 C to - 70 C.

Muscle, hypodermis and gastrointestinal epithelium from adult female Ascaris lumricoides var. summ were found to contain serotonin based upon glyoxylic acid induced histofluorescence and indirect immunolabeling with an anti-serotonin monoclonal antibody conjugated to protein A-colloidal gold.

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