Browsing by Author "Loubser, J. T."
Now showing 1 - 3 of 3
Results Per Page
Sort Options
- ItemDual cultures of meloidogyne javanica and grapevine rootstocks on artificial media(South African Society for Enology and Viticulture, 1990) Loubser, J. T.; Meyer, A. J.Grapevine rootstock cultivars were cultured on more than one artificial medium. Meloidogyne javanica was inoculated on the roots of different cultivars on seven media and penetration and development were recorded. Plate cultures of roots allowed microscopic examination of nematode development. Nematode reproduction occurred on susceptible rootstocks only, suggesting similar results for field and in vitro screening. However, root and nematode development was low and inconsistent, indicating problems which will have to be resolved before general application of the technique.
- ItemPopulation dynamics of the root-knot nematodes meloidogyne incognita (kofoid & white) chitwood and m. javanica (treub) chitwood on grapevines in two different regions of South Africa(South African Society for Enology and Viticulture, 1987) Loubser, J. T.; Meyer, A. J.Two root-knot nematode species, Me/oidogyne incognita and M.javanica, were studied with regard to their seasonal population fluctuations on grapevines growing in two vastly different climatic areas. Regular observations on reproduction and numbers of larvae in the soil were compared with patterns of root growth, soil temperature and moisture. Population fluctuations of the two species showed similar trends in spite of the climatic differences in the two areas, but M. incognita in the northern Cape reached higher populations. Larvae populations in the soil declined in summer in both areas and increased during autumn to reach peaks in winter. With the onset of root growth in spring, larvae numbers decreased in the soil, as a result of large scale root penetration.
- ItemResistance of grapevine rootstocks to meloidogyne incognita under field conditions(South African Society for Enology and Viticulture, 1987) Loubser, J. T.; Meyer, A. J.Resistance of grapevine rootstocks to root-knot nematodes (Meloidogyne incognita) was studied in field trials. Resistance was found to be adequately expressed by the degree of galling. A highly significant positive correlation exists between nematode populations in the soil as well as nematode reproduction and galling, while grapevine growth and yield were negatively related to the degree of infestation. However, information regarding rootstock tolerance and intolerance (sensitivity) was not considered reliable. It was further shown that a susceptible scion would not lower the resistance of the rootstock involved. Based on their rate of galling, rootstocks Ramsey, 99 Richter PS, Dogridge, Freedom, Harmony and 101-14 Mgt are resistant while Jacquez, 140 Ruggeri, Grezot-1, Maleque 44-53 and Constantia Metallica are susceptible.