Fluensulfone and fluopyram have high nematicidal activity against second-stage juveniles of Meloidogyne spp. However, information about their activity against Meloidogyne egg viability is limited. In this study, the effect of these compounds alone and in combination on the hatching, mobility and infectivity of hatched M. incognita and M. javanica juveniles was investigated. Continuous exposure of M. javanica eggs to fluopyram for 3 days at ≥5.0 mg/L completely prevented hatching. ED50 values of fluopyram for hatching inhibition of M. incognita and M. javanica eggs by continuous exposure for 12 days were 1.5 and 0.6 mg/L, respectively. However, inhibition by 3-day exposure to 5–100 mg/L fluopyram was mostly reversible after rinsing in water. In contrast, both nematode species hatched during the 3-day exposure to fluensulfone, even at 100 mg/L; however, almost no new hatching occurred after rinsing eggs exposed to 50 and 100 mg/L fluensulfone in water. ED50 values of fluensulfone for hatching inhibition of M. incognita and M. javanica eggs were 28.1 and 42.7 mg/L, respectively, by 3-day exposure followed by 12-day incubation in water. More than 70% of the juveniles hatched from M. incognita and M. javanica eggs treated with fluensulfone at 25–100 mg/L were immobile after rinsing, and the M. incognita eggs from these treatments lost 49–99% of their viability. Mixtures of these compounds did not have a significant synergistic effect on hatching or juvenile immobilization compared to treatments with each compound alone, but their interaction was significant for infection.
