Nematicidal activity of Carica papaya L. seeds and leaf extracts on Meloidogyne species isolated from infected Solanum lycopersicum L. in Nigeria
Active metabolites from plants with nematicidal properties are considered safer to the environment, non-toxic to man than synthetic chemicals for the control of plant parasitic nematodes. An in-vitro nematicidal activity of (Carica papaya) seeds and leave extracts on Meloidogyne species, infecting Solanum lycopersicum L (tomato) was carried out in the nematology laboratory University of Jos, Nigeria. The seed and leave of Carica papaya were dried at 26oC, ground into powder and extracted with distilled water. The root-knot nematodes were isolated by Baerman method and identified by comparative morphology, descriptive and lattice keys. The juveniles were exposed to varied concentrations (0.75, 1.5, 3.0 and 6.0 mg/mL) of the extracts incorporated in 1ml of homogenized nematodes suspension (50 juveniles) replicated three (3) times for different times of 6, 12, 18 and 24 hours. Data of immobilized/dead nematodes was recorded for each period. Phytochemical screening of the extract was carried out using standard methods. The data was analyzed using Analysis of variance (ANOVA). The result showed that aqueous seed extract of Carica papaya caused 100% nematode juvenile mortality at the highest’s concentration (6 mg/mL) within 24 hours of exposure while the leaf extract of Carica papaya caused 100% mortality within 24 hours of exposure. The result revealed that the higher the concentration of both seeds and leave extracts of Carica papaya the higher the mortality of root-knot juveniles. The effect varied significantly with concentration of the extracts at P<0.05. The bioactive Phyto substances of the test plant revealed the presence of alkaloids, carbohydrates, flavonoids, anthraquinones, tannins, steroids/terpenes, saponins, Cardiac glycosides. This suggests that the extracts contain bioactive substances which were active on Meloidogyne species.
Keywords: Carica papaya, Meloidogyne species, Nematicidal, Solanum lycopersicum
*Correspondence: danahapluka@yahoo.com, 08036199739
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