DEVELOPMENT OF ROOT-KNOT AND ROOT-NODULES ON COWPEA AS INFLUENCED BY SULPHUR DIOXIDE

Abstract

The effect of SO[sub2] at 0.1 ppm on the development of root-knot disease caused by Meloidogyne incognita and root nodulation by Rhizobium was studied on two cultivars of cowpea viz. V-38-1 and V-218 in artificial treatment condition. Single and combined effects of SO[sub2] and the nematode on plant growth and dry matter production were also determined. The nematode and SO[sub2], independently caused significant suppression of plant growth and dry weights. The suppressions were synergistic in the combined treatments of the two stresses. Sulphur dioxide induced foliar chlorosis on both the cultivars of cowpea which appeared earlier in the presence of root-knot nematode. Galling and egg mass production were greater on the exposed plants. Development of functional nodules was significantly suppressed in all the treatments.