Interactions of Meloidogyne javanica, Fusarium udum and Rhizobium on pigeon pea in the presence of nickel and cobalt as pollutants

Abstract

SummaryThe interactions between Meloidogyne javanica, Fusarium udum and Rhizobium on pigeon pea, in the presence of nickel (Ni) and cobalt (Co) as soil pollutants, were studied. In single inoculations, M. javanica caused a reduction in plant growth, particularly at higher inoculum levels (1000 and 10 000 JJ2). Fusarium udum induced wilting symptoms and the higher concentrations of Ni and Co suppressed plant growth. Meloidogyne javanica and F. udum interacted to show more severe wilting symptoms than F. udum alone. Wilting was completely inhibited by Ni but reductions in plant growth and nodulation occurred. In the presence of Ni, M. javanica did not cause galling but nodulation was suppressed. Cobalt also suppressed wilting and nodulation but interacted with M. javanica to increase root galling and to reduce plant growth by a greater amount than the total of reductions caused by the individual treatments.