Elevated Soil Temperatures Impact Nematode Reproduction Biology

Plant-parasitic nematodes are one of the economically most important pathogens, and how rising soil temperatures due to climate change impact their ability to damage crops is poorly understood. The current study was conducted to evaluate the reproduction biology (reproduction and virulence) of Rotylenchulus reniformis and Meloidogyne floridensis on tomato at soil temperatures of 26 °C (control), 32 °C, 34 °C, and 36 °C. The reproduction and virulence of both nematode species were differentially impacted by soil temperature. Relative to the control, the increase in reproduction of R. reniformis ranged from 20% to 116% while that of M. floridensis ranged from 22% to 133%. The greatest reproduction of R. reniformis was observed at 34 °C while that of M. floridensis was observed at 32 °C. Across all temperatures, reproduction of M. floridensis was 2.9 to 7.8 times greater than the reproduction of R. reniformis, suggesting that the former nematode species has a greater fecundity. The rates of change in reproduction relative to the controls were greater in M. floridensis than in R. reniformis, indicating that the latter nematode species is more resilient to changes in soil temperature. The virulence of both nematode species increased numerically or significantly at 32 °C and 36 °C, but not at 34 °C. The greatest virulence of both nematode species was observed at 36 °C at which 57% and 60% root biomass was lost to R. reniformis and M. floridensis, respectively, compared to the root biomass of uninoculated plants at that temperature. The results of the current study suggested that crop damage by nematodes will likely increase as global soil temperature continues to increase.