Management of Meloidogyne incognita Populations by Crop Rotation in a Small-Scale Field Trial and Nematode Pathogenic Effects on Selected Cultivars

Abstract

The density of field populations of the root-knot nematode. Meloidogyne incognita Race 1, was suppressed and maintained at a low level for 3 yr in a small-scale crop rotation trial. The cropping sequence from mid-August, 1978, to early January, 1982, was: a 3:1 mixture of red and white sorrel (Hibiscus sabdariffa); a 5-wk weed fallow; cassava (Manihot esculenta); a 1- and 3-mo weed and clean fallow, respectively; chinese cabbage (Brassica chinensis); maize (Zea mays); red kidney beans (Phaseolus vulgaris); a mixed crop of cowpeas (Vigna unguiculata) and callaloo (Amaranthus viridis); and finallv, red sorrel. The density of Pratylenchus sp. increased in cassava and maize rhizosphere soil while those of Helicotylenchus sp. and Rotylenchulus reniformis increased in maize and cowpea rhizosphere soil. Tylenchorhynchus sp. density increased during the cultivation of red kidney beans and callaloo intercropped with cowpeas. Roots of the first crop of red sorrel and maize yielded large number