Pathogenic Potential Of Root- Knot Nematode (Meloidogyne Arenaria)To Common Zinnia (Zinnia Elegans) And Its Management Using Coffee Husk And Biochar

Abstract

Root knot nematodes are capable of infecting over 3000 host plants including, ornamental plants. It is widely distributed and damaging Zinnia elegans flowers. Widespread dissemination and lack of information regarding this ornamental plant damage due to plant-parasitic nematodes is attributed to demand research for agronomic crops and an important avenue for distribution of other plant-pathogenic organisms. The aim of this study was to identify and evaluate the Pathogenecity of Meloidogyne arenaria on common zinnia, and to manage the nematode using coffee husk and biochar amendments. All experiments were conducted in Jimma University College of Agriculture and Veterinary Medicine (JUCAVM). The host status experiment was carried out on common zinnia plant on infected soil under greenhouse. Pathogenecity study and nematode pest management experiments per pot were laid out using completely randomized design (CRD) under greenhouse condition at JUCAVM. Seedlings with four true leaves were inoculated with J2 a week after transplanting. Data on number of eggmass and root gall, final nematode population, reproduction factor, plant height, root length, leaf number, fresh weight of shoots and roots were collected from each treatment in all experiment after two months of inoculation. The results of host status showed that the growth rate of plant (height, root length, leaf number, fresh weight of shoots and roots) were increased with time. Aboveground symptoms developed over time due to infection. The maximum nematode populations (26715), numbers of root gall (506) and eggmass (483) were noted 16th week after infection. The result of Pathogenecity study showed that the initial inoculum level increases the number of galls, eggmass and final nematode population. The highest number of galls122.0), eggmass (66.33) and final nematode population (25114.3) were noted on 16J2/g soil, but for nematode reproduction factor was achieved at inoculum level of 2 J2/g soil (6.45). Application of coffee husk and biochar amendment reduced the root galling and final populations of M. arenaria compared with control. The lowest nematode populations were recorded at 4:1 ratio from coffee husk and biochar (200,925) respectively while the highest was noted on non-amended plants (29695). Coffee husk was more effective than biochar in reducing population of nematodes. Amendment of soil with coffee husk and biochar may provide practical control of root knot nematodes as a part of integrated management system. However, further research is needed to evaluate their efficacy under field condition.