Hoplolaimus galeatus

 

Contents

 

Rev 12/10/2019

Lance Nematode  Classification Hosts
Morphology and Anatomy Life Cycle
Return to Hoplolaimus Menu Economic Importance Damage
Distribution Management
Return to Hoplolaimidae Menu Feeding  References
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Classification:

        Tylenchina
        Tylenchoidea
         Hoplolaimidae
          Hoplolaiminae

     Hoplolaimus galeatus (Cobb, 1913) Thorne, 1935 

    Synonyms:
      Nemonchus galeatus Cobb, 1913
      Hoplolaimus coronatus Cobb, 1923
      Hoplolaimus tylenchiformis Andrassy, 1958
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Morphology and Anatomy:


A-F = female; G,H = male

Female: Cephalic region offset usually with 5 annules, forming an low cone generally with flattened sides.  Basal annule with 32-36 longitudinal striations seen in face view.  Cephalic framework yellowish, massive, differing in details between sexes.  

Stylet knobs with anteriorly directed processes.  

Esophageal glands with 3 nuclei.  

Hemizonid about 2 annules long, situated just anterior to excretory pore which is near level of esophago-intestinal valve.  

Hemizonion about 5 annules posterior to pore, caudalid about 8 annules anterior to anus.  

Ovaries outstretched, spermathecae round to oval.  Epiptygma single or double, usually conspicuous.  

Intestine overlapping rectum and usually extending into tail. 

Tail rounded, with 10-16 annules.  

Lateral field with 4 incisures, usually areolated, but occasionally only partly so.

Male: Cephalic region higher and less conoid than female, hemispherical with convex sides.  Similar to female in other respects.

Spicules 40-52 µm long, slightly arcuate. 

Gubernaculum with titillae; gubernaculum may be bent distally in some specimens.  


[Ref: CIH Descriptions of Plant-parasitic Nematodes, Set 2, No. 24 (1973)]

 

Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:

 

 
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Distribution:

Widely distributed in the U.S., especially on woody or graminaceous plants.

 

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Economic Importance:

 

 

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Feeding:

Primarily endoparasites.  

Feeding occurs in root cortex of both lateral and mycorrhizal short roots, where the nematode causes considerable damage in its migration parallel to the long axis.  

In root cortex of cotton, nematode prefers phloem.  

Damage to vascular tissue is more extensive than to cortex, abnormal division of phloem parenchyma or tylose production in the xylem sometimes occurring in response.

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Hosts:

Cotton, pine, oak, sycamore, wheat, carnation, cranberry, grasses, sugarcane, clover, vetch, grape, peach; highly pathogenic on turfgrass in Florida.

For an extensive host range list for this species, click

 


 
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Life Cycle:

Ecophysiological Parameters:

For Ecophysiological Parameters for this species, click If species level data are not available, click for genus level parameters

Few aspects of biology and life-history have been investigated.  

Population increase has been studied on cotton (Krusberg & Sasser, 1956), cranberry (Bird & Jenkins, 1964), and bermuda grass (Di Edwardo, 1963).

Population dynamics has been investigated in other grasses and legumes (McGlohon et al., 1961), red pine seedbeds following chemical treatment (Sutherland & Adams, 1966), and cotton following Paspalum notatum (Rodriguez-Kabana & Pearson, 1972).

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Damage:

Hoplolaimus galeatus damage (right) to roots of St. Augustine's grass (University of Florida photograph).

Note loss of feeder roots.

Infected cotton plants grown under conditions of limited moisture are susceptible to stunting, yellowing, and defoliation.  

In cotton, the nematode feeds primarily endoparasitically causing considerable cortical damage during penetration.  

Infected pine seedlings are devoid of healthy lateral roots and mycorrhizae.  High nematode population levels can reduce root weight of Pinus clausa by 54% (Ruehle, 1972).  Pine seedlings can suffer 50% mortality.  

In sycamore, high inoculum levels caused extensive root necrosis and marked decrease in fresh weight.  

After 75 days, peach seedlings growing in soil infected with Fusarium oxysporum and H.  galeatus were markedly smaller than controls or combinations of fungus and other nematode species tested (Wehunt & Weaver, 1972).

Hoplolaimus galeatus damage on St. Augustine's grass (University of Florida photograph)

Hoplolaimus galeatus damage on Bermuda grass (University of Florida photograph)

 

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Management:

Fumigants - pre-plant treatment of plant rows with 1,3-Dichloropropene (1,3-D) produced taller pine trees after 5 years than trees growing in untreated rows.  

Treatment with Nemacur gave 3 months' field control on bermuda grass.  

Population can be reduced, but not eliminated, if infested soils are left fallow for 16 months.

Host Plant Resistance, Non-hosts and Crop Rotation alternatives:

For plants reported to have some level of resistance to this species, click

 

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References:

CIH Descriptions of Plant-parasitic Nematodes, Set 2, No. 24 (1973)]

H. Ferris

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Copyright © 1999 by Howard Ferris.
Revised: December 10, 2019.