EVALUATION OF DIFFERENT LEAF POWDER AND EXTRACTS IN CONTROLLING ROOT KNOT NEMATODE [Meloidogyne javanica (Chitwood) 1949] ON SWEET MELON IN YOLA, ADAMAWA STATE NIGERIA

Abstract

Laboratory and field experiments were conducted in the year 2020 and 2021. Laboratory experiment was carried out at the Department of Crop Protection Modibbo Adama University, Yola, in September, 2020 to evaluate the effect of three plant extracts (Datura stramonium, Tamarin Indica and Vitex doniana) at different concentrations on juvenile mortality of Meloidogyne javanica. In the laboratory, aliquots of crude, 5, 10 and 15 ml each of the water-soluble plant extracts of D. stramonium, T. indica, V. doniana and distilled water as the control were dispensed using 10 ml syringe into 45 petri dishes containing 1000 second stage juveniles of M. javanica in 10 ml of water. Counts of dead nematodes were carried over 72 hours. The field experiments were carried out in two planting seasons (2020 and 2021). The field experiment consisted of four treatments (powder of D.stramonium, T. indica,V. doniana and control) replicated three times and arranged in split plot design. Data were collected on both above and below ground parts of the plant, galling index and final nematode population. The Laboratory results revealed that the crude extracts of D stramonium at 72 hours gave 97 % juvenile mortality, followed by T. indica ( 85 %), V. doniana (19 %) and the least (0 %) in the control. The laboratory results also shows that the higher the concentration and time of exposure the higher the mortality and vice versa. The field results for both 2020 and 2021 revealed that D. stramonium treated plants recorded the longest vine length, highest number of leaves, number of fruits (23 and 24), and fruit weight (703 and 709 g), fresh vine weight (325 and 339.8 cm), root length (21 and 22.2 cm) and the lowest galling index (12.58 and 11.68) and nematode populations (155 and 158) respectively. For the cultivars, Jimeta local cultivar recorded better growth parameters and yield as well as fewer galling index and nematode population. It can be concluded that the plant materials had the potential for use as nematicides which could possibly replace the hazardous synthetic nematicide in the near future. It is recommended that further laboratory and field trials be carried out to ascertain the exact phytochemicals responsible for the efficacy of D. stramonium before recommending to farmers.