Belonolaimus longicaudatus

  

Contents

  

Rev 10/16/08
Sting Nematode  Classification Hosts
Morphology and Anatomy Life Cycle
Return to Belonolaimus Menu Economic Importance Damage
Distribution Management
Return to Belonolaimidae Menu Feeding  References
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Classification:

      Tylenchida
       Tylenchina
        Tylenchoidea
         Belonolaimidae
          Belonolaiminae

  Belonolaimus longicaudatus Rau, 1958 

    Synonyms:
      none.

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Morphology and Anatomy:

Female: Length 2.0-3.0 mm.

Lip region hemispherical, divided bylateral, dorsal, and ventral grooves into 4 main lobes (2 subdorsal and 2 subventral) each bearing 6 or more horizontal striations; two smaller lobes (lateral) with amphid apertures. Lip region generally set off from body by deep constriction, but this may be less marked in some populations. Labial morphology as revealed by SEM is discussed in Smart et al. (1972).

Lateral field marked by a single incisure extending from base of lip region to near tail terminus.

Spear 100-140 µm, thin, flexible, with rounded knobs; when retracted, spear causes the esophageal tube to become convoluted.

Excretory pore posterior to median bulb with hemizonid just anterior to it.

Esophageal glands lobe-like extending over anterior end of intestine.

Vulva a transverse slit, vulval lips not protruding, vagina generally with opposing pair of sclerotized pieces in lateral view; two ovaries, amphidelphic, outstretched. Spermathecae present.

Tail 115-189 µm long, generally about 5 times anal body width, with rounded terminus. Hyaline portion 5.9 µm long. Phasmids inconspicuous. Intestine extending almost to terminus. There are well pronounced serpentine lateral canals present which become visible at about the level of esophageal gland lobe and extend to the tail extremity.
Males: Length, male: 2.0-3.0 mm.

Lip region in outline more flattened at the sides than in female; arrangement of lobes similar.

Testis outstretched. Spicules arcuate with ventral flanges; distal ends pointed with small apical notches. Gubernaculum well developed. Bursa enveloping tail.

Belonolaimus gracilis is distinguished from B. longicaudatus by shorter tail, longer spear, and greater relative width. Different populations of B. longicaudatus show variations in spear knob shape, head shape, size and ratios, shape of spicules, and in vulva sclerotization. All populations have 8 chromosomes.

[Ref: CIH Descriptions of Plant-parasitic Nematodes, Set 3, No. 40 (1974) and H. Ferris.]
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Distribution:

A plant-parasitic nematode of major importance in the southeastern U.S. Reported in Alabama, Arkansas, North and South Carolina, Louisiana, Mississippi, Florida, Kansas, Virginia, New Jersey and Oklahoma. In North-central Florida, 35,000 acres of vegetable land are infested. Nematode not reported outside of U.S.

In 1992, a 3-4 acre infestation was found at a golf course near Palm Springs in Southern California, further sampling has located the nematode on four golf courses in the Rancho Mirage area of Coachella Valley.

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Economic Importance:

A-rated pest in California.  

Rancho Mirage infestation triggers eradication or containment legislation.

Note the danger of movement into surrounding agricultural areas.  Also concerns regarding spread in turf e.g. re-sodding of Candlestick Park for 1993 NFC championship game with turf from the Coachella Valley.

   

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Feeding:

Migratory ectoparasite at root tip and along sides.  

Long stylet penetrates to inner cortex and endodermis; causes root tip damage, resulting in reduced root system with short, stubby branches. 

Gall-like swellings may occur at root tips in corn due to repeated production of new root branches.  

Feeding causes lesions on cotton roots, followed by root girdling.

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Hosts:

Wide host range: cereals, vegetables, celery, sweet corn, strawberries, cotton, forage crops, trees, ornamentals, turf (excellent host), and pasture.  

Tobacco is a non-host.  

North Carolina populations have distinctly different host ranges, although some hosts are suitable for these and other populations. 

Of 60 plant species tested for host status to the B. longicaudatus population in the Coachella Valley, only three were non hosts (Bekal and Becker).

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Life Cycle:

Nematode prefers light, sandy soils (>80% sand with particle size 120 to 320 µm [65 mesh], 10% clay); B. longicaudatus does not reproduce well in soils with a composition outside these parameters.

Reproduction is inhibited in soils with large amounts of organic matter.

Soil moisture is also important; optimum reproduction occurs at 7% soil moisture; some reproduction occurs at 3% soil moisture; reproduction and development are inhibited at 30% moisture (Robbins, 1973?).

Aeration of water increased survival of nematodes at 30% moisture, suggesting that soil aeration may be very important (Robbins, 1973?).

The effect of temperature has also been studied; at 35 C, Georgia populations of B. longicaudatus survived, but North Carolina populations did not; at 25 to 30 C, both Georgia and North Carolina populations flourished (Robbins, 1973?).

Males and females are present, but life history details are not well understood.

In general, nematodes are confined to the upper 30 cm of soil, but within this zone there is vertical and seasonal fluctuation depending on temperature. High air temperatures force nematodes deeper into the soil, while lower surface temperatures result in a higher concentration of nematodes in the surface layers, with little or no increase below (Boyd & Perry, 1971).

Evidence of genetic diversity is provided by reproductive compatibility among populations:

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Damage:

Devastating on cotton - causes complete crop failures when associated with Fusarium wilt; renders Fusarium wilt-resistant cotton susceptible.

Also causes damage to vegetables, peanuts, and soybeans in the Southeastern coastal plains. Infected plants show an increased tendency to wilt in dry conditions, severe stunting, leaf chlorosis; plant death may occur. 

Belonolaimus longicaudatus damage to peanuts (left), nematode-free control on right.

Belonolaimus longicaudatus damage to bermuda grass.

Most destructive pest of turfgrass in Florida (Busey et al., 1991).

Infested areas vary in size and shape, but the boundary between diseased and healthy plants is usually well-defined.

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Management:

1.  Nematicides

Organophosphate and carbamate nematicides are effective.  ethylene dibromide (EDB) at 10 gpa also was used on peanuts and other crops.  Use of granular nematicides such as Aldicarb and Nemacur is successful in controlling nematode populations.                                              

2.  Crop rotation

Crop rotation is less effective due to wide host-range of the nematode.                                      

3.  Cultural Methods

Tomerlin (1969) found that numbers of B. longicaudatus were reduced in soils amended with alfalfa meal, cottonseed meal, and rice straw. 

Heald & Burton (1968) reported that application of organic nitrogen (activated sewage sludge) reduced populations of B. longicaudatus on bermuda grass and was superior to inorganic nitrogen.

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References:

 

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Copyright © 1999 by Howard Ferris.
Revised: October 16, 2008.