Thermal influence on the embryonic and post embryonic development of Meloidogyne graminicola.

Meloidogyne graminicola poses a significant threat to global rice production, causing yield losses between 17% and 30%. This study aims to elucidate the effects of temperature on the embryonic and post-embryonic development of M. graminicola. The egg shape index (ESI) of M. graminicola was determined, revealing that most eggs were ellipsoidal with an average ESI of 39.10 ± 1.3 μm. Embryogenesis at 28 ± 2℃ was characterized by rapid cellular division, with the development progressing from a single-cell stage to a multi-cell stage within 29 h. The first-stage juvenile (J1) emerged after 159–162 h, and hatching occurred at around 292–295 h at 28 ± 2℃. At 17 ± 2℃, embryonic development was slower, with J2 emerging after 552–554 h and hatching at 561–570 h. No development was observed at 6 ± 2℃ and 40℃, with embryos arrested at the blastula and two-cell stages, respectively. The lifecycle of M. graminicola was completed in 14–16 days at 28 ± 2℃, while it took 35–36 days at 17 ± 2℃, highlighting the significant influence of temperature on nematode development. At the higher temperature, J2 penetrated rice roots within 24 h and developed into egg-laying adults by day 16. At the lower temperature, penetration occurred on day 6, with adult females forming by day 28. The study highlights the significant impact of temperature on the development and lifecycle of M. graminicola, providing insights into its biology and thermal requirements in paddy. These findings are crucial for understanding the nematode’s adaptability and may inform strategies for managing M. graminicola infestations in rice cultivation. [ABSTRACT FROM AUTHOR]