Penetration and development of root-knot nematode, Meloidogyne incognita alone and in presence of wilt fungus, Fusarium oxysporum in susceptible and resistant cultivars of cowpea*

Ten day old seedlings of cowpea cultivars viz; Pusa Komal (susceptible to bothnematode and wilt fungus) and C-152 (resistant to nematode and susceptible to wilt fungus) were inoculated separately with Meloidogyne incognita @ 2 J₂/g soil, both alone and in presence of wilt fungus, Fusarium oxysporum (inoculated simultaneously) in 4 cm diameter plastic pots containing 200 g sterilized soil. Maximum penetration of M. incognita in both the treatments i.e., (nematode alone and nematode + fungus simultaneously) in both the cultivars occurred upto 7 days after inoculation. In the roots of Pusa Komal, 21 to 28 days were required by M. incognita (in both the treatments) to complete its development from 2nd stage to adult stage. However, in C-152, M. incognita took 32 days for development. In C-152, besides reduced penetration, a delayed development of second stage larva to adult with a marked increase in the number of males was observed. No significant difference was observed in respect to penetration and development of M. incognita within the roots subjected to nematode alone or in presence of F. oxysporum in either of the cowpea cultiwars.