Cover Crop Management in Vineyards of the Lower Orange River Region, South Africa: 2. Effect on Plant Parasitic Nematodes

Abstract

This study was conducted as part of a larger investigation into the effect of management practices on selected sown cover crops and the effects thereof on grapevine performance. The aim of this study was to determine the effect of these cover crops on plant parasitic nematode populations under natural field conditions. The trial site was in an own-rooted Sultanina vineyard situated in the Lower Orange River of the Northern Cape Province. Three management practices were applied selectively to ten cover crop species, with two control treatments consisting of weeds. Nematodes were monitored for a period of four years. 'Saia' oats were indicated as being poor hosts to both root-knot and root-lesion nematodes, while 'Overberg' oats showed poor host status against ring nematodes. 'Midmar' ryegrass and 'Paraggio' medic were also poor hosts for root-knot nematodes, while grazing vetch appeared to be a good host for root-knot nematodes. The most notable result from this study was the relatively high numbers of all three nematodes on the vine row, as opposed to the inter-row where cover crops were established. This indicates that vines were much better hosts for these nematodes than the cover crops. It is recommended that if more definite trends are to be observed, Brassica species, which have direct toxic/repellant effects on nematodes, should be tested. (Smith, 1977;Kleynhans et al., 1996). Root-knot and dagger nematodes are amongst the most economically significant. No research has been done on the use of cover crops for nematode management in South African vineyards. In California, Dactylis glomerata L. ('Berber' orchardgrass) was found to reduce root-knot nematode numbers in vines interplanted with this cover crop (Wolpert et al. 1993). In Australia, McLeod & Warren (1993) found that increases of root-knot nematodes were higher on legume crops than on cereals or Brassica species. A summary of the nematode host status of various cover crops and commonly occurring weeds in vineyards is given by Nicol & Heeswijck (1997). Most of the research focus thus far has been on root-knot nematodes.In South Africa, vineyard production is moving more towards an integrated pest management (IPM) approach, in line with the Scheme for Integrated Production of Wine (promulgated under the Act on Liquor Products [Act 60 of 1998]). Cultural management practices and the biological control of pests form the basis of IPM and should be viewed in the context of all pests and their natural enemies. Addison & Samways (2006) found that ants (a secondary pest of the vine mealybug Planococcus ficus Signoret) were not affected significantly by cover crop management with Vicia dasycarpa Ten. (grazing vetch), Triticale v. Usgen 18 (triticale) or Festuca arundinacae L. v. Cochise (dwarf fescue) compared to weeds (no sown cover crop, full surface chemical control from bud break to harvest). Triticale, however, did appear to promote ant foraging, while mealybug natural enemies preferred the natural weed plots. Dust is detrimental for hymenopteran parasi...

Management of service crops for the provision of ecosystem services in vineyards: A review

“…Another mechanism involved in the reduction of pest pressure is the production of allelochemicals by service crops. Some authors suggest selecting Brassica species which are known to have direct deterrent or toxic effects on plant parasitic nematodes (Addison and Fourie, 2008).…”

Accelerated Microbial Degradation of Nematicides in Vineyard and Orchard Soils

“…The most important plant-parasitic nematode species found in South African vineyards and deciduous fruit orchards include Criconemoides xenoplax (Raski, 1952) (Addison & Fourie, 2007), of which C. xenoplax and Meloidogyne spp. are known to be the most damaging to vines and deciduous fruits (Storey, 2007).…”

Chemical control of <i>Meloidogyne spp.</i> in grapevines (<i>Vitis vinifera</i>)

“…are important pests of grapevine (Vitis vinifera L.) which may cause up to 60% yield loss (Nicol and Heeswijck, 1997;Riley and Walker, 2006;Pietsch and Burne, 2008;Australian Wine Research Institute, 2010). Several pest management techniques including resistant rootstocks (McKenry and Anwar 2006;Gutiérrez et al, 2011;Ferris et al, 2012), plant extracts and bioagents (Mervat et al, 2012), organic matter to complement plant nutrition and promote biological control agents (Adb-El-Khair et al, 2009;Australian Wine Research Institute, 2010), cover crop management inside vineyards ( Quader et al, 2001;Addison and Fourie, 2008;Kruger et. al., 2015) to reduce pest dispersal, and chemical control (Rajendan and Naganathan 1978;Loubser and Meyer, 1986;Australian Wine Research Institute, 2010) have been tested with varying degrees of success.…”