Punctodera chalcoensis		Contents		Rev 10/05/2023
Mexican Corn Cyst Nematode		Classification		Hosts
		Morphology and Anatomy		Life Cycle
Return to Punctodera Menu		Economic Importance		Damage
		Distribution		Management
Return to Heteroderidae Menu		Feeding		References
		Go to Nemaplex Main Menu		Go to Dictionary of Terminology

Classification:

      Tylenchida
       Tylenchina
        Tylenchoidea
         Heteroderidae
          Punctoderinae

           Punctodera chalcoensis Stone, Sosa Moss and Mulvey, 1976

    Synonyms:
      None.

Mexican corn cyst nematode

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Morphology and Anatomy:

	Females: Cyst stage present. Body globose, spherical to pear-shaped with short neck and no terminal cone, white color.  Head with one or two prominent annules. Stylet slender, often curved, with rounded basal knobs. Esophagus strongly developed with massive, circular median bulb with prominent valve.   Two large ovaries filling the enlarged body cavity which in mature females is occupied by eggs. Cuticle greatly thickened except in head region, covered with a rugose or lace-like pattern of shallow ridges, with a sub-surface pattern of rows of fine refractive punctations.  Vulva a short transverse slit centered in a circular zone lof thin cuticle - the vulval fenestra. Anus, a transverse slit smaller than the vulva and dorsal to the vulva in a thin-walled circular anal fenestra . Eggs retained in body (no egg mass) but a very small gelatinous matrix observed on some specimens.  (Stone et al., 1976). Cysts pale to dark brown, darkening with age. Thin walls of the vulval and anal fenestrae are lost in old cysts.
Cysts of P. chalcoensis  on corn roots - Photographs by Ignacio Cid del Prado Drawings of P. chalcoensis from Stone et al., 1976	Cyst with both vulval and anal fenestrae: Photgraph by Ignacio Cid del Prado Vera
	Males:  Typical heteroderid male morphology. Body vermiform, ventrally curved and twisted through 180 degrees  Lateral field with four lines. Stylet well developed with shallow basal knobs, flat to concave anteriorly. Single testis. Spicules greater than 30 um long, slightly curved, distally pointed. No cloacal tubus. Tail very short, rounded.
Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:

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Distribution:

Reported from areas above 2000 m in the Mexico, Tlaxcala and Pueblo States of Mexico, mainly in sandy soils.

Probably indigenous to Central Mexico and co-evolved with maize (Stone et al., 1976).

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Economic Importance:

Considered of extreme importance on maize in its area of distribution.  Causes evere plant damage, especially in soils of volcanic origin (McDonald and Nicol, 2005).

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Feeding:

Nurse cell system is a syncytium.

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Hosts:

Corn, Zea mays and teosinte, Zea mexicana.  These were the only hosts out of 300 graminaceous plants tested (McDonald and Nicol, 2005). Note that wheat and many grasses are hosts of the related P. punctata.

Cysts of Punctodera chalcoensis attached to the root of Zea mays Photograph by Ignacio Cid del Prado Vera

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Life Cycle:

Ecophysiological Parameters:

One generation per year.

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Damage:

 Heavily attacked Zea mays plants have stunted root systems with many short laterals. Aerial parts of the plants appear unthrifty.

Greater damage is observed when rainy season starts early after planting than when onset of rain is delayed, possibly be due to greater hatch, mobility and invasion of juveniles in the moister soil.

Management:

Resistance

No resistance was found in a wide range of maize varieties or in thirteen separate isolates of teosinte (Stone et al., 1976). However, over 300 other graminaceous plants were non-hosts..

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

Non-hosts include Avena sativa (7 varieties), A. f atua, Triticum aestivum ( 14 varieties ), Secale cereale (11 varieties ), triticale (12 varieties), Sorghum vugare (119 varieties ), Agropyron spp.(6), Bromus spp. ( 2 ), Dactylis sp., Elymus sp., Festuca spp. (3), Lolium spp. (2) and Phleum sp. (Stone et al., 1976).

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References:

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Copyright © 1999 by Howard Ferris.
Revised: October 05, 2023.