As feeding continues, the juvenile molts to the third stage and fourth stage, before molting a fourth time to become the male or female adult. Since each of these stages is vermiform, the nematode can move freely in soil to new feeding sites on the same or new roots, or can locate a sexual partner. Eggs are laid singly in the soil around roots. Depending on the species, a single adult plant parasitic female may lay up to 2,800 eggs. After a period of embryogenic development, which may last from a few days to several weeks, the eggs are ready to hatch.
Eggs provide an overwintering stage for many nematode species.
Thus, a proportion of eggs laid in autumn may not hatch until the soil temperature increases in spring. The fourth stage of certain genera, including Paratylenchus , also shows some resistance to unfavorable environmental conditons. Phytonematology Study Guide. University of California, Division of Agriculture and Natural Resources.