New insights into the life-stage development and life-cycle duration of Meloidogyne enterolobii, M. incognita and M. javanica

Abstract Meloidogyne enterolobii is a highly pathogenic nematodes species that renders host plant resistance ineffective that exists for other species. The life-cycle development, duration, and reproduction potential of three Meloidogyne species occurring in South Africa, viz. M. enterolobii, M. incognita and M. javanica were determined in roots of three crops: tomato (‘Moneymaker’), soybean (‘DM-5953-RSF’) and maize (‘P-2432-R’) under glasshouse conditions. During time intervals 3-, 5-, 10-, 15-, 20-, and 25-days after inoculation (DAI), 20 randomly selected individuals, representing different life-stages of each species, were isolated from crop roots. Meloidogyne enterolobii had a quicker life cycle development compared to the other two species. Mature females were observed 15 DAI for all three species, but single eggs of M. enterolobii were present at 15 DAI opposed to egg masses only found 20 and 25 DAI for the other two species. Second generation motile J2 were observed for M. enterolobii and M. javanica from 20 DAI and at 25 DAI for M. incognita. Substantially shorter degree days (DD) were recorded for M. enterolobii being 216 for tomato, 195 for soybean and 232 for maize; for M. incognita it was 292 for tomato, 264 for soybean and 314 for maize; and for M. javanica it was 276 for tomato, 248 for soybean and 298 for maize. The use of genotypes with shorter growing periods is suggested to play a crucial role in preventing more generations of M. enterolobii developing which is foreseen to potentially result in higher population densities and severe crop damage.