Influence of temperature on the development of the temperate root-knot nematodes Meloidogyne chitwoodi and M. fallax

Hatching, migration, invasion and post-penetration development of Meloidogyne chitwoodi and M fallax were examined at 15, 20 and 25°C. The optimum temperature for hatching of second-stage juveniles (J2) of M chitwoodi and M fallax was 20°C. However, temperatures above 20°C and no higher than 25°C were more favourable for hatching of M chitwoodi than M fallax J2, which in contrast hatched in greater number at temperatures below 20°C and no lower than 15°C. Meloidogyne chitwoodi J2 migrated farther and in higher numbers than those of M fallax in sand columns. The optimum temperature for migration was 20°C for M chitwoodi and 25°C for M fallax. Invasion of roots by both nematodes was higher on potato than maize at all temperatures. For both nematodes the degree-days (DD₅, base temperature 5°C) required for completing their life cycle were 555-740 DD₅ on potato and 705-740 DD₅ on maize. Temperature played a more important role in post-penetration development than the host plant. The behavioural differences found between M chitwoodi and M fallax are discussed in relation to different survival strategies of the two species.