Cotton Damage Thresholds of Root Knot Nematodes in the Presence of Fusarium Spp

Meloidogyne enterolobii damage thresholds were tested on cotton in the presence of Fusarium oxysporum. Sterile sandy soil was inoculated with F. oxysporum (10⁶ conidia/ml) in the greenhouse and cotton was seeded using both root knot nematode susceptible and resistant varieties. Four population levels (50, 100, 175, and 250 juveniles/100 cc soil) of M. enterolobii typically associated with low risk to high risk of damage under normal conditions were evaluated to determine if the interaction with F. oxysporum changes damage thresholds in cotton. Damage was assessed through plant biomass and roots were rated for galling and weight. Nematode egg counts were taken using the sucrose floatation method to measure reproduction of M. enterolobii.