Effects of nitrogen fertilisers on the Javanese root-knot nematode Meloidogyne javanica and its interaction with cucumber

Abstract

The influence of different nitrogen salts at five electrical conductivity levels (EC 2, 4, 6 and 8 mmhos/cm) on the Javanese root-knot nematode (RKN) (Meloidogyne javanica) and its interaction with cucumber was evaluated under in vitro, growth chamber and greenhouse conditions. Percentages of egg-hatching and second-stage juvenile viability of M. javanica were greatly reduced when NH₄Cl, (NH4)₂SO₄ and NH₄NO₃ were used especially at the higher levels of EC and accompanied with reduction in cucumber root galling. The lower root galling (less than 2.5) was accompanied with NH₄Cl, (NH₄)₂SO₄ and (NH₄)₂HPO₄, while KNO₃ and NH₄NO₃ resulted in moderate root galling. In contrast to the nitrogen salts, NaCl caused a reduction in both nematode infection and root growth especially at higher EC levels and this could be due to salinity effect. Diammonium phosphate was superior over the tested salts in increasing plant and root fresh and dry weights and cucumber phosphorus content, while KNO₃ was superior in increasing in plant content of potassium.

Keywords:

• management
• nematode-plant interaction
• salt suppression

Acknowledgements

This work is part of research project was financially supported by Scientific Research Support Fund of Jordan in co-ordination with the Scientific Research Deanship of Mutah University, Karak, Jordan.