Nematode Diversity in Banana Rhizosphere From West Bengal, India

Survey on plant and soil nematodes associated with banana plantations in different banana growing districts of West Bengal (India), revealed that the occurrence of the most economically important genera of plant parasitic nematodes were Pratylenchus, Meloidogyne, Helicotylenchus, Tylenchorhynchus, Hoplolaimus, Rotylenchulus, Hirschmanniella, Criconemoides. Altogether there were seventeen species of plant parasitic nematodes viz. Pratylenchus coffeae, P. brachyurus, P. similis, Meloidogyne incognita, M. javanica, Hoplolaimus indicus, Rotylenchulus reniformis, Helicotylenchus multicinctus, H. abunaamai, H. incisus, H. gratus, H. dihystera, Tylenchorhynchus nudus, T. mashhoodi, T. coffeae, Hirschmanniella mucronata and Criconemoides sp. Among the plant parasitic nematodes, P. coffeae, P. brachyurus, M. incognita, H. multicinctus and R. reniformis were found as serious pests of banana in West Bengal. The occurrence of the most damaging species, Radopholus similis and Heterodera oryzicola was not detected in West Bengal, although R. similis is reported to occur in Midnapore and Jalpaiguri. Distribution of plant parasitic nematodes associated with the rhizosphere of banana in important banana growing districts of West Bengal, was presented on the basis of information available in the state. Observation of the effects of some banana cultivars/types on the nematode fauna, showed that the cooking banana type Musa (ABB) cv. Kanchakala and Musa (BBB) cv. Seed Banana supported a huge population of M. incognita which induced severe root galling symptoms. The lesion nematode, P. coffeae was found infesting all the cultivars/types. It maintained high population densities in the rhizosphere of Musa (AA) cv. Matti and Musa (ABB) cvs. Kanchkala, Krishna Kanthali whereas the Seed Banana cultivar had a suppressive effect on P. coffeae. The rhizosphere of banana cultivar, Matti exhibited a high population of H. multicinctus, R. reniformis population was recorded in extremely high levels in the rhizosphere of all cultivars/types. Free-living nematodes including rhabditids, dorylaimids, mononchids, were found in abundance in the banana rhizosphere.