Influence of castor, Ricinus communis L. as relay crop in controlling root knot disease of groundnut caused by Meloidogyne arenaria (Neal) chitwood

Root knot disease of groundnut caused by Meloidogyne arenaria is a serious problem in a few farmers’ fields of Junagadh and Rajkot districts in Saurashtra region of Gujarat. An experiment was conducted during kharif season 2002-03-04 and 2005 in farmers’ fields in Junagadh district to find out the effect of relay crops viz., castor (GCH-4), pigeon pea (BDN-2), and sesame (G Til-1) in groundnut in combination with nematicide in managing M. arenaria. The data on nematode population, root-knot index and pod equivalent yield data revealed that relay cropping of groundnut with castor (row ratio of 2:1) along with soil application of carbofuran 3G @ 1 kg a.i./ha was highly effective in managing the root knot disease and also in increasing the yield with a CBR of 1:2.35.