Browsing by Author "Kruger, D. H. M."

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    Control potential of brassicaceae cover crops as green manure and their host status for meloidogyne javanica and criconemoides xenoplax
    (South African Society for Enology and Viticulture, 2015-12) Kruger, D. H. M.; Fourie, J. C.; Malan, Antoinette P.
    Laboratory bioassays were undertaken to determine the potential of Avena sativa cv. Pallinup (Pallinup oats), Sinapis alba cv. Braco (white mustard), Brassica napus cv. AV Jade (canola), Brassica juncea cv. Caliente 199 (Caliente) and Eruca sativa cv. Nemat (Nemat) to suppress Meloidogyne javanica (root-knot nematode) and Criconemoides xenoplax (ring nematode) when applied as green manure. The host status of the crops also was determined during glasshouse trials. Plant material of the different cover crops was macerated and mixed with nematode-inoculated soil. After a period of 14 and 28 days respectively, susceptible tomato plants were planted in the soil, where they were left to grow in a glasshouse, prior to the performance of a root gall index. The same procedure was followed for C. xenoplax, except that, in this case, the nematodes were extracted from the soil after 14 and 28 days to determine the impact of the plant biomass on nematode numbers. To determine the host status of the cover crops concerned, potted plants were inoculated with the two nematode species. Results from the bioassays showed significant suppression of M. javanica by white mustard, Caliente 199 and Nemat. However, no significant differences were found in the C. xenoplax bioassays. In the M. javanica glasshouse host trials, Nemat was classified as a poor host. In the C. xenoplax host trials, canola was found to have a suppressing effect on C. xenoplax. The results are the first to show the effect of biofumigation on C. xenoplax nematode.
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    Cover crops with biofumigation properties for the suppression of plant-parasitic nematodes : a review
    (South African Society for Enology and Viticulture, 2013-08) Kruger, D. H. M.; Fourie, J. C.; Malan, Antoinette P.
    Plant-parasitic nematodes are a problem in vineyards worldwide, with some species acting as vectors of grapevine soil-transmitted viruses. Global pressure on the use of soil-applied chemical nematicides has led to a search for new control options, or for alternative methods to suppress plant-parasitic nematodes as part of integrated pest management. This paper gives valuable background information on the use of cover crops with biofumigation properties for the suppression of plant-parasitic nematodes in vineyards.
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    The effect of cover crops and their management on plant-parasitic nematodes in vineyards
    (South African Society for Enology and Viticulture, 2015) Kruger, D. H. M.; Fourie, J. C.; Malan, Antoinette P.
    In South Africa the use of annual cover crops is an established soil cultivation practice in vineyards that is environmentally friendly and financially sustainable in the long term. Species from the Brassicaceae family are well known for their biofumigation potential. In this study, Sinapis alba (white mustard), Brassica napus cv. AV Jade (canola), Brassica juncea cv. Caliente 199 (Caliente), Eruca sativa cv. Nemat and Avena sativa cv. Pallinup were established as cover crops in a vineyard for three growing seasons and evaluated for their biofumigation impact, as well as crop host impact on the suppression of economically important plant-parasitic nematodes. Mechanical and chemical cover crop management practices on Criconemoides xenoplax (ring nematode) and Meloidogyne javanica (root-knot nematode) numbers were determined. Canola and Caliente showed a consistent reduction of C. xenoplax present in the vine row 60 days after the management practices applied at the end of the third growing season. This trend was found during the three-year trial period for all different sampling periods (0, 15, 30 and 60 days). Lowered numbers for the total plant-parasitic nematodes were also found for the three-year trial period measured at 60 days after the management practice sampling period. The results can be attributed mainly to the crop host status of the two cover crop species towards C. xenoplax. White mustard showed a constant increase in C. xenoplax numbers in the vine row over the three-year period compared to the treatments in which no cover crop was sown.
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    Effect of management practices applied to cover crops with biofumigation properties on cover crop performance and weed control in a vineyard
    (South African Society for Enology and Viticulture, 2015) Fourie, J. C.; Kruger, D. H. M.; Malan, Antoinette P.
    This five-year trial (2009 to 2013) was carried out in a full-bearing seven-year-old Shiraz/101-14 vineyard established on a sandy to sandy clay loam soil at Blaauwklippen farm (33°58’S, 18°50’E) near Stellenbosch, South Africa. Fourteen treatments were applied, consisting of two management practices applied to five cover crop species, winter-growing weeds (no cover crop), and winter-growing weeds (no cover crop) combined with a nematicide application in the vine row. The dry matter production (DMP) increased between 0.55 and 2.62 t/ha from 2009 to 2010 for the small-seeded Sinapis alba cv. Braco (white mustard), Brassica napus cv. AVJade (canola), Brassica juncea cv. Caliente 199 (Caliente) and Eruca sativa cv. Nemat (Nemat). This was attributed to the finer seedbed that could be created. All cover crops suppressed the winter-growing weeds throughout the study. Although the stand of summer-growing weeds differed significantly between treatments in 2010, 2011 and 2012, the cover crop treatments did not suppress these weeds significantly. However, for the duration of the study, the weed stand in the canola controlled chemically full surface (CC) during grapevine bud break tended to be lower than that of the canola controlled mechanically (MC) during grapevine bud break. The same trend occurred between CC and MC for Avena sativa cv. Pallinup (Pallinup oats) and the treatments in which no cover crops were sown, with the exception of in 2009 and 2010 respectively.