Effect of chestnut tannins on the root-knot nematode Meloidogyne javanica

Among the natural products extracted from plants, tanninshave been reported to possess antihelmintic propertiesespecially for gastrointestinal nematodes in ruminants.Also, they are toxic to a wide range of fungi, bacteria andyeasts. Therefore, an in vitro and a glasshouse pot experimentswere undertaken to evaluate the effect of chestnuttannins on the control of the root-knot nematode Meloidogynejavanica. In the in vitro experiment, different tanninconcentrations in a geometric scale (from 0.32 to 20.48g/l), were tested for their effect on hatching of the nematode,whereas in the pot experiment, 100, 250 and 450g/m2 of tannins in aqueous solutions, were used in pots attransplant or at transplant and two weeks later for theireffect on nematode control. In both experiments treatmentswere compared to untreated and fenamiphos-treated controls.In vitro a nematostatic effect of tannins was observed,whereas in the pot experiment a significant reductionof eggs and juveniles/g root, total population densityand reproduction rates of the nematode were recorded. Theanatomical changes induced by M. javanica in tomatoroots treated with tannins did not differ from those producedby this and other Meloidogyne species on varioushosts reported earlier.