Meloidogyne hapla Chitwood, 1949
Northern root-knot nematode
Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:
Temperate regions or at higher
altitudes in warmer areas worldwide; also occurs on alfalfa in southern
C-rated pests in Californian
Feeding site establishment and
development typical of genus.
Type Host: Potato (Solanum tuberosum).
Over 550 hosts listed by 1965; these
include vegetables, clover, alfalfa, and ornamentals.
Minimum, optimum, and maximum
temperatures (C) recorded for M.
Reproduction in M.hapla is usually parthenogenic but can also be
sexual. However, when sexual crosses were made between diploid and
polyploid isolates of a population, some of the offspring were hermaphroditic (Triantaphyllou,
1993). This is the only known case of hermaphroditism in the Tylenchida,
although it is known in the Rhabditida and Mononchida. It is considered an
abberation in that hermaphrodites were morphological females in which the gonad
initially produced eggs and then converted to sperm production. By the
time sperm were produced, eggs had a hardened shell and could not be
fertilized. That differs from
Caenorhabditis elegans in which the
gonad produces about 300 sperm late in the 4th juvenile stage. Those sperm
are stored in the spermatheca and fertilize eggs that are produced later.
Since M. hapla hermaphrodites produced only a few eggs before
converting to sperm production, understanding the underlying mechanism could
result in manipulation of the lifecycle to reduce population growth (Triantaphyllou,
Small spherical galls, often with root
proliferation at gall.
Some recorded yield losses
Meloidogyne hapla is also
associated with other pathogens in disease complexes.
Clean planting material by using hot water
treatment (60 min. at 45.5 Ã‚Â°C);
Dips in DBCP were used on
ornamentals when that nematicide was available.
rotation useful (grasses and cereals are often non-hosts).
Host Plant Resistance, Non-hosts
CIH Descriptions of Plant-parasitic Nematodes, Set 3, No. 31 (1974)
Triantaphyllou, A.C. 1993. Hermaphroditism in Meloidogyne hapla.
Journal of Nematology 25:15-26.