Nematode inoculum density and plant growth period to screen coffee genotypes to Meloidogyne paranaensis

Summary The standardisation of procedures to study pathogen-host interaction has always been a challenge for researchers, especially in the field of nematology. One of the critical points is defining the initial densities of nematodes and the optimal time after inoculation to evaluate experiments. This study aimed to determine the initial population densities of Meloidogyne paranaensis in susceptible coffee seedlings, with the goal of optimising experiments focused on selecting coffee genotypes in relation to their response to this nematode under glasshouse conditions. For this purpose, ‘Mundo Novo’ coffee seedlings with five pairs of leaves were cultivated in 945 cm 3 pots and inoculated with different population densities of M. paranaensis per plant (700, 1400, 2800, 5600 and 11 200). They were evaluated at 90, 120, 150 and 180 days after inoculation to determine the nematode reproduction factor (RF). The results indicate that M. paranaensis populations between 700 and 2800 nematodes, evaluated between 90 and 180 days after inoculation, demonstrated more consistent and accurate results regarding the RF values obtained compared to larger nematode populations.