Abstract
A rapid and highly sensitive assay method to evaluate the infectivity of Meloidogyne incognita second-stage juveniles (J2s) is reported. Among the substrates to grow a seedling in a plant culture tube, nursery soils composed of small granular soil particles were the best both in root growth and ease of substrate removal from the root. As a host plant, balsam and cucumber were considered the most appropriate host plants for the assay in the test tube among the 6 plant species. Twenty J2s individuals were inoculated onto a 1-week-old balsam or cucumber seedling in a culture tube containing granular nursery soil, and nematodes in the root system were stained by the acid fuchsin method 1 week after inoculation. The number of infected nematodes increased and then plateaued at seven days after inoculation in both types of seedlings. To demonstrate the efficiency of this method, 1-week-old balsam seedlings were infected with fosthiazate-treated J2s in the presence of fosthiazate and dosedependent infective suppression was observed in the treated J2s. This method enables us to use a small number of nematodes as an inoculum for infection assays and to complete the assay within two weeks from the sowing of seeds.
