Life Cycle
Attracted by exudates released by the coffee roots, J2 nematode (migratory stage) moves toward to food source. The nematodes penetrate in the roots and search for a site to feed on. Several cells are selected to start uptaking food. Those cells are modified and grow bigger (hypertrophy) without cellular division. However, nuclei division start happening and many nuclei are produced inside generating giant cells. Surrounding cells will suffer hyperplasia and start cellular division wildly. For M. exigua, these cells will become galls, but not for M. coffeicola. The nematode starts to swell and get a swollen shape as it molts through the juvenile stages until the adult stage. Many eggs will be produced by the female nematode, and released in a gelatinous mass. M. exigua lays its eggs under the epidermis, unlike M.coffeicola that lays them outside of the roots. The juveniles that came out in the gelatinous mass will hatch and find a new feeding site and restart the cycle. Some juveniles may become males when the nematode population is high (competition), environmental condition are not favorable, or the plant is resistant. The lifecycle of Meloidogyne exigua was reported to be around 35 days at 25-30C.
Read more about this topic: Coffee Root-knot Nematode
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