NATURAL FLUCTUATIONS OF SCUTELLONEMA-BRADYS (NEMATODA, HOPLOLAIMIDAE) DURING GROWTH AND STORAGE OF THE YAM (DIOSCOREA-ALATA) IN MARTINIQUE

During the growth of yam in Martinique, Scutellonema bradys develops successively in the seed tuber and the roots which constitute the intermediate focus of infection and finally in the neo-tuber. However, the highest rate of multiplication of the nematode was observed in the tuber after harvest. The adult females transfer the infection from the seed to the newly formed parts. The time of abundant multiplication of the nematode seems to correspond with the appearance of the necrotic areas and coincides with the initiation of the dormancy (and therefore the interruption of the respiration) of the tuber. The weight loss of an infested tuber reached approximately 30% whereas an uninfested one loses only 10%.