Author : Chin Chiew Lan

Summary : Large scale hydroponic crop production is a recent technology in Malaysia, with Universiti Agriculture Malaysia (UPM) playing a lead role in research and development. Since its inception in 1982, pre- and post-emergent damping-off in cucumber, muskemelon and tomato seedlings had been frequently observed. Isolation of Phythium spp. from roots of wilted manure cucumber, muskemelon, and tomato plants were done at UPM, Malaysia Agricultural Research and Development Institute (MARDI), and FIMA in Fraser's Hill. The mature muskmelon plants exhibited drastic interveinal chlorosis and yellowing of young and old leaves at the onset of fruiting. It was accompanied by general necrosis of the root systemresulting in subsequent plant's death. Isolation of PYTHIUM spp. implicated them to be the causal agent. Since little is known about their role and control in the hydroponic system in Malaysia, studies were undertaken to characterize and identify the PYTHIUM spp., establish their pathogenicity, determine the sources of inoculum, and investigate the in-vivo efficacy of some fungicides for their control. Through cultural and morphological studies, three pythium spp. namely P. myriotylum, P. splendens and a non-sporulating Pythium sp. were identified from six isolates obtained.