Effect of sugar beet plant residues on population density of root knot nematode, Meloidogyne incognita infecting cowpea and biochemical changes in treated plants

Different sugar beet residues, fresh and dry leaves and mashed storage roots of sugar beet @20 and 10g were tested for controlling root knot nematode, Meloidogyne incognita on cowpea in screen house. On the basis of the average percentages nematode reduction, mashed storage roots at the highest rate (20g) achieved 85.1% increase followed by dry leaves at the same rate caused the reduction 81.6%. Average nematode reduction (79.5%) was caused by using fresh leaves of sugar beet at the highest rate followed by that occurred by the lowest one compared to untreated control. Plant growth, number of nodules (produced by nitrogen fixing bacteria, Rhizobium) and yield followed the same trend as the highest rate of sugar beet residues was used; there was the highest percentages increase of plant growth, yield and number of nodules. It is clearly noticed that soluble carbohydrates, total carbohydrates, phenols and soluble proteins in seeds increased at the different treatments compared to those of the untreated check and the effect, in general, was higher by using the highest rate compared to the lowest one. On the other hand, the contents of chlorophyll a, chlorophyll b and carotenoids in leaf increased at untreated check compared to those at different treatments.