Effectiveness of plant-derived formulations against the root-knot nematode Meloidogyne incognita (Kofoid et White) Chitw. in a protected tomato crop

The effectiveness of two plant-derived formulations for the control of the root-knot Meloidogyne incognita (Kofoid et White) Chitw. was evaluated in a protected tomato crop in Southern Italy. A neem oil-based formulation and a commercial mixture of aqueous extracts of Quillaja saponaria Molina (80%), Yucca schidigera Roezl (10%) and Tagetes spp. (10%) were tested in comparison with the standard chemical oxamyl and an untreated control. All tested formulations significantly decreased soil nematode population and average root galling compared to the untreated control. However, nematode infestation was found significantly lower in plots treated with oxamyl or neem formulation than in those treated with quillay-based product. Tomato yield did not significantly differ among treatments. Satisfactory yield obtained by quillay-based product appears to be caused by the biostimulating effect of quillay extract on tomato plants