Suppression of Heterodera cajani by Pasteuria penetrans during three successive plantings of cowpea

Studies were undertaken to ascertain the extent of suppression of Heterodera cajani by Pasteuria penetrans during three successive plantings of cowpea. Number of cysts and juveniles (J₂) decreased significantly in treatments receiving combined inoculations of H. cajani and P. penetrans compared to the treatment receiving H. cajani alone at the harvest of each planting with maximum reduction being 60.5 and 87.2% in cyst and J₂ populations respectively. Cyst infection increased from 6% at the harvest of first planting to 50% at the harvest of third planting. Average number of eggs per cyst also decreased significantly at the harvest of each planting in the presence of P. penetrans than without it. All the plant growth characters, except root length, increased significantly at the harvest of second planting in treatments receiving H. cajani and P. penetrans together than H. cajani alone. The damage caused by H. cajani was competely offset by P. penetrans at the harvest of third planting and the growth was at par with control (without H. cajani and P. penetrans)