Meloidogyne genus of root-knot nematodes include major agricultural parasites of a wide range of crops worldwide. Host plants include Solanaceae (tomato, egg plant, potato), Cucurbitaceae (melon, cucumber), Leguminosae (bean), carrot, salsify, lettuce, witloof chicory, artichoke, mangold, celery, etc. Species of Meloidogyne show an outstanding diversity in it's host plants: some of them are extremely polyphagous (with up to 3000 host plants) while the others are restricted to very specific hosts. They also have been know for extreme cytogenetic diversity and thier mode of reproduction ranges from obligatory amphimixis to obligatory parthenogenesis.

Meloidogyne hapla is adapted to colder climates. M. hapla is one of the most cytologically and reproductively diverse Meloidogyne species. Ploidy levels vary and reproduction may be by mitotic parthenogenesis, facultative meiotic parthenogenesis, or cross-fertilization. Genetic and physical map of M. hapla genome is under construction at the University of California, Davis.