Barley root-knot nematode.
The specific name is derived from the initials of the UK National Agricultural
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.
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.
Feeding site establishment and
development typical of genus.
Type Host: Spring barley (Hordeum vulgare).
Grasses, cereals, and weeds.
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).
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,
rotation can be effective in California (1 year fallow or 2
of potatoes increased barley yield - Allen, 1970).
Host Plant Resistance, Non-hosts
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.
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,