EFFECT OF INDIGO (Indigofera tinctoria L.) GREEN MANURING ON THE PROPERTIES OF SOIL AND THE CONTROL OF ROOT-KNOT DISEASE OF BRINJAL CAUSED BY NEMATODE (Meloidogyne javanica)

Abstract

A pot experiment was carried out in Hajee Mohammad Danesh Science and Technology University, Dinajpur, Bangladesh during the period from 10 March, 2016 to 10 August, 2016 to study the effect of indigo (Indigofera tinctoria L.) on the properties of soil and the control of root-knot disease of brinjal caused by nematode (Meloidogyne javanica). In this experiment brinjal plants were used as test crop and indigo (Indigofera tinctoria L.) as green manuring crop. The experiment was laid out by seven treatments with three replications. The treatments were T0 = Control, T1 = 200 egg mass, T2 = 200 egg mass + indigo green manuring, T3 = 400 egg mass, T4 = 400 egg mass + indigo green manuring, T5 = 200 egg mass + furadan and T6 = 400 egg mass + furadan. Indigo had significant effects on the soil properties, growth of the shoots and roots of brinjal plants. Height of the brinjal plants were recorded before harvesting the plants and the length of the roots, their dry weights and the number of gall g-1 of roots were recorded. It was clearly found that the growth of shoots and roots were highest for the control treatment but reduced for the egg mass of root-knot inoculated brinjal plants. The highest plant height (58.83 cm) and the root length (36.89 cm) were found in T5 treatment where minimum gall was formed. On the contrary, the lowest plant height and roots length were 28.50 cm and 20.05 cm, respectively for the 400 eggs mass inoculated treatment. Application of indigo and furadan also increased the shoots and roots growth and decreased the gall numbers even having egg mass of root-knot inoculation. Same results were found for the shoot and root weights of brinjal plants. Maximum shoot and root weights of 16.00 g and 4.57 g were found in T5 and T2 treatments, respectively. Only in the 400 eggs mass inoculated treatment the shoot and root weights were 7.28 g and 1.13 g which increased after green manuring with indigo or application of furadan. 200 eggs pot-1 inoculated brinjal plants formed 85.53 galls g-1 of root which increased to 105 galls g-1 root due to 400 eggs pot-1 inoculation. Indigo green manuring markedly decreased the galls g-1 of root compared to those without indigo manuring. Furadan application also reduced the galls number but indigo green manuring reduced more galls than that of the furadan application. The negative correlations between the galling incidence and plant height and between the galling incidence and root length of brinjal plants revealed that the indigo green manuring was effective in increasing the growth of the brinjal by suppressing the nematode activity.