Population changes of Macrophomina phaseolina and Fusarium oxysporum f. sp. cumini in oil-cake and crop residue-amended sandy soils

Abstract

Population changes of Macrophomina phaseolina and Fusarium oxysporum f. sp. cumini were followed in a sandy soil amended with mustard and castor cakes or nitrogen-enriched pearl millet residue, singly or in combined form. Populations of both the pathogens were reduced by 100% in the mustard-cake-amended soil within a period of 30 days after addition. Amendment with nitrogen-enriched pearl millet residue significantly reduced the population of M. phaseolina within 45 days, but not that of F. oxysporum. However, incorporation of pearl millet residue in both types of cakes delayed the rate of reduction. The induced suppressiveness in the cake-amended soil was associated with a substantial increase in the population of antagonistic actinomycetes. These results suggest that amendment of soil with mustard cake in fields infested with M. phaseolina and F. oxysporum f. sp. cumini may reduce yield loss caused by dry root rot of guar ( Cyannopsis tetragonoloba (L.) Taub.) and wilt of cumin ( Cuminum cyminum L.).