Rev 11/07/2023
Tylenchida Tylenchina Tylenchoidea Heteroderidae Meloidogyninae
Meloidogyne naasi Franklin, 1965
Barley root-knot nematode. The specific name is derived from the initials of the UK National Agricultural Advisory Service.
Review general characteristics of the genus Meloidogyne.
Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:
Temperate areas of the United States and Europe. Originally described from field crops (cereals, grasses, sugarbeet) in England and Wales.
B-rated pest in California Nematode Pest Rating System.
In California, this species can cause yield losses of 50-75% in barley grown under continuous cropping in the Tulelake innermountain region.
Sedentary endoparasite.
Feeding site establishment and development typical of genus.
Type Host: Spring barley (Hordeum vulgare).
Grasses, cereals, and weeds.
Ecophysiological Parameters:
Haploid chromosome number n=18; reproduction is by facultative meiotic parthenogenesis. The egg nucleus undergoes a meiotic reduction division; one member of each pair of chromatids remains in a haploid nucleus and the other in a polar body. If fertilization by a male sperm occurs, the diploid number of chromosomes is restored. Otherwise the somatic number of chromosomes is restored by fusion of the egg pronucleus with the polar body from the reduction division (Subbotin et al., 2021; Triantaphyllou, 1985).
Egg hatch in water is very limited unless eggs have been chilled by storage below 5C for 1 to 7 weeks (Franklin et al, 1971).
Galls are generally cylindrical, spindle-shaped, or hooked. Heavily infected plants are stunted, have a yellowish appearance and may die. Surviving plants tend to remain stunted and do not produce normal seed heads (Allen et al., 1970; Scaheck, 2023).
Feeding causes necrosis, hyperplasia, and hypertrophy of cortex; also causes disorganization of xylem elements.
Severely affected plants wilt readily, even when soil moisture is sufficient, because galled roots have less ability to absorb and transport water. Nutrient deficiency symptoms including chlorosis may result from the reduced ability of galled roots to absorb and transport nutrients, even when levels are adequate in the soil. Stunting is a frequent result (Scheck, 2023).
Crop rotation can be effective in California (1 year fallow or 2 seasons of potatoes increased barley yield - Allen, 1970).
Host Plant Resistance, Non-hosts and Crop Rotation alternatives:
Allen, M., Hart, W. and Baghott, K., 1970. Crop rotation controls barley root-knot nematode at Tulelake. California Agriculture, 24(7), pp.4-5.
CABI CPC 2022. Meloidogyne naasi. https://www.cabidigitallibrary.org/doi/10.1079/cabicompendium.33250
CIH Descriptions of Plant-parasitic Nematodes, Set 2, No. 19 (1973)
Franklin, M.T., 1965. A root-knot nematode, Meloidogyne naasi n.sp. on field crops in England and Wales. Nematologica 11: 75-86.
Franklin, M.T., S.A. Clarke and J.A. Course. 1971. Nematologica 17:575-590.
Scheck, H.J. 2023. California Pest Rating Proposal for Meloidogyne naasi Franklin 1965 Barley root knot nematode CDFA, Sacramento, California, USA
Subbotin, S.A. Palomares-Rius, J.E., Castillo, P. 2021. Systematics of Root-knot Nematodes (Nematoda: Meloidogynidae). Nematology Monographs and Perspectives Vol 14: D.J. Hunt and R.N. Perry (eds) Brill, Leiden, The Netherlands 857p.
Triantaphyllou, A.C. 1985. Gametogenesis and the chromosomes of Meloidogune nataliei: not typical of other root-knot nematodes. J. Nematology 17:1-5.
Triantaphyllou, A.C. 1985. Cytogenetics, cytotaxonomy and phylogeny of root-knot nematodes. In Sasser, J.N. & Carter, C.C. (eds) An Advanced Treatiswe on Meloidogyne.Vol 1. Biology and Control.N.C. State Universty Graphics, Raleigh, N.C. USA.