Title : Managing root-knot nematodes in potatoes using cucurbitacin-containing phytonematicides: A success story in South Africa.
Abstract:
All commercially available potato cultivars in South Africa do not have resistance to all root-knot (Meloidogyne species) nematodes in the country. In the past, the potato industry relied heavily on the use of fumigant nematicides for successful production of economic potato crop. However, with the withdrawal of fumigant synthetic nematicides from the agrochemical markets and the high residues of systemic nematicides in tubers, alternative management strategies were researched and developed. The objective of this study was to compare the efficacy of cucurbitacin-containing phytonematicides and existing non-fumigant nematicides on nematode suppression and growth of potato plants. Field studies were initiated to assess the efficacy of Nemarioc-AL phytonematicide, Nemafric-BL phytonematicide, Aldicarb and Velum on suppression of Meloidogyne species on potato cv. ‘Mondial G3’. At harvest, in some cases the phytonematicides had outdone the synthetic nematicides, whereas in other cases the efficacies on nematode suppression were comparable. Generally, when the phytonematicides were used in granular formulation during planting in a separate trial, the products were not phytotoxic, but they successfully suppressed nematodes and improved tuber yield. In conclusion, cucurbitacin-containing phytonematicides are highly effective in managing population densities of the South African Meloidogyne species.
