New insights into synergistic interactions of root-knot nematode and wilt causing fungi on pigeon pea in sandy loam soil

A study under pot conditions was undertaken to know the relationship between plant biomass and inoculum densities of Meloidogyne incognita. Similarly, plant biomass—Fusarium udum relationship was also observed. Results revealed that increased inoculum densities resulted in corresponding decrease in plant biomass markers. Compared to control plants, 2000 nematode inoculation caused significant damage in phytobiomass (23.07–26.32%) of pigeon pea. 2.0 g F. udum inoculation caused significant impairment in different plant growth characteristics (22.96–26.02%) over control plants at P < 0.05. The interactive study revealed that concomitant, M. incognita + F. udum inoculation caused the maximum reduction (33.68–56.66%) in plant biomass. Next to this, M. incognita inoculation 15 days prior to F. udum and F. udum inoculation 15 days prior to M. incognita caused an impairment of (28.55–50.11%) and (23.99–43.33%), respectively. However, they were statistically either at par or non-significant over each other. Disease assay revealed that M. incognita multiplication rate was correspondingly augmented upon the rise of nematode concentration, conversely, the reproduction factor was progressively decreased. Pathogens interactive facet revealed that M. incognita inoculated plants showed a higher root galls (99.40), eggs (79.20), fecundity (199.80), and nematode population (13,785.60). The presence of F. udum suppressed nematode multiplication ability. However, concomitant inoculation of M. incognita and F. udum aggravated percent wilt severity (65.48%) thus exhibiting a synergistic interaction between the vascular pathogens.