Reaction of green manure plants to root knot nematodes

Abstract

Green manure plants are increasingly being adopted for soil fertility improvement especially in low-input agriculture. Information on their reaction to plant parasitic nematodes is, however, scanty. Green manure plants, Calliandra calothyrsus, Canavalia ensiformis, Chenopodium quinoa, Crotalaria juncea, Desmodium uncinartum, Gliricidia sepium, Leucaena leucocephala, Mucuna pruriens, Tephrosia purpurea, 1ithonia diversifolia and Vicia villosa, were evaluated to determine their reaction to root knot nematodes in glasshouse and field experiments. Sesbania sesban and Tagetes minuta were included as susceptible and resistant checks, respectively. In the glasshouse, 15 em-diameter pots were each filled with steam-sterilised soil infested with 10,000 eggs and juveniles (J2) of Meloidogyne javanica. The field experiment was conducted in a field naturally infested with Meloidogyne javanica and M. incognita. Ninety days after soil infestation, galling and egg masses were quantified using a scale of 1-9. Second stage juveniles (J2) were also extracted from 250 cm3 soil. Differences in galling and egg masses were significant (p=0.05) among the green manure plants evaluated. The plants could be grouped into three categories with V. villosa, and T purpurea being rated as susceptible. Calliandra calothyrsus, C quinoa and C. ensifomis were moderately resistant while C. juncea, D. uncinartum, G. sepium, L leucocephala, M. pruriens, and T. diversifolia were rated as resistant. Root knot-nematode resistant green manure plants should, therefore, be recommended in areas where the nematodes are constraint to crop production Key words: Calliandra calothyrsus, Canavalia ensiformis, Chenopodium quinoa, Crotalaria juncea, Desmodium uncinartum, Gliricidia sepium, Leucaena leucocephala, Meloidogyne javanica, M. incognita, Mucuna pruriens, Tephrosia purpurea, 1ithonia diversifolia and Vicia vil/osa.