Effects of root-knot nematode (Meloidogyne javanica) on lemon balm medicine; plant (Melissa officinalis)

Lemon balm (Melissa officinalis) is one the beneficial medicinal plants that has a long history in curing various human diseases. In this study, while assessing the pathogenicity of root-knot nematode, Meloidogyne javanica, on lemon balm medicinal plant, the effects of various initial inoculum density of nematode in host plant growth indices and nematode reproduction were investigated. Then chemical compounds in the plant leaves were assessed after 90 days of nematode infection using Gas- Chromatography (GC/MS). Results showed the susceptibility of the lemon balm to the target nematode. While increasing the nematode initial density, shoot fresh and dry weight and shoot and root length decreased, while root fresh and dry weight increased. There was an inverse relationship between the initial nematode density and reproduction factor (RF). The highest and the lowest RF observed with the lowest and highest nematode initial density respectively. (Z)-caryophyllene, hydroxyl citronellal, borneol,-humuleneα , carophyllene oxide, terpinene-α, isoborneol, trans-pulegol, trans-carveol, citronellol and dihydro citronellol acetate are those compounds which increase in inoculated host plants.