Phatu William

Title : Cucurbitacin-containing phytonematicides induce concentration-responses on selected nutrient elements in leaf tissues of green bean

Abstract:

Cucurbitacin-containing phytonematicides consistently reduce nematode population densities in various crops. However, there is no information on how these products affect the accumulation of essential nutrient elements in crops. The objective of this study was to determine the influence of Nemafric-BL and Nemarioc-AL phytonematicides on accumulation of essential nutrient elements in leaf tissues of green bean (Phaseolus vulgaris) under greenhouse conditions. Weekly application of phytonematicides each at 0, 2, 4, 8, 16 and 32%, were assessed on plant growth variables, nematode suppression and nutrient elements (Ca, K, Na, Fe, Zn) in leaf tissues of green bean at 56 days after initiating the treatments. Phytonematicide concentrations significantly affected nematode numbers and nutrient elements, without affecting plant growth. Calcium (R² = 0.97), K (R² = 0.93), Na (R² = 0.94) and Fe (R² = 0.91) each with increasing Nemafric-BL phytonematicide concentration exhibited positive quadratic relations. In contrast, K (R² = 0.97) and Fe (R² = 0.98) each with increasing Nemarioc-AL phytonematicide concentration exhibited positive quadratic relations, whereas Na (R² = 0.92) and Zn (R² = 0.72) each with increasing phytonematicide concentration exhibited negative quadratic relations. In conclusion, accumulation of essential nutrient elements in green bean leaf tissues and increasing phytonematicide concentrations exhibited concentration-dependent growth patterns prior to the eventual expression of plant growth responses.

Biography:

Professor P.W. Mashela from South Africa is senior Professor of nematology at the University of Limpopo and specialises in research and development of phytopesticides, with special interest in cucurbitacin-containing phytopesticides.