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Pest Description
IDENTITY: Scientific name: Punctodera chalcoensis
Stone, Sosa Moss & Mulvey, 1976
 Common name: Mexican corn cyst nematode

NOTES ON TAXONOMY AND BIOLOGY: This cyst forming nematode has sedentary endoparasitic habits. Cysts are persistent  (> 10 years) tanned sacs derived by the female body and contain eggs. Cysts of this species are subspherical or ovoid, lack posterior protuberance, have large vulval and anal fenestrae and are provided by small bullae. Second-stage juveniles (J2) emerge from the cysts, penetrate host roots and establish a specialized feeding site (syncytium) in the stele. They develop becoming swollen females, which retain the eggs, rupture root cortex and protrude from the root surface. At the end of the reproductive phase, females die and become dark brown cysts.

GEOGRAPHICAL DISTRIBUTION: This cyst forming nematode has been reported only in Mexico (CAB International, 2001).

HOSTS: Corn (Zea mays) is the primary agronomic host of this nematode, which infects teosinte (Zea mexicana).

CROP LOSSES: Punctodera chalcoensis is a serious pest of corn in Mexico. When associated with fungi, P. chalcoensis can cause yield suppression by 90% (Sosa-Moss, 1987).

MEANS OF MOVEMENT AND DISPERSAL:  Through root material, soil debris, and poorly sanitized bare root propagative plant material.

RATING: (M) Due to the volume of trade with Mexico, the economic importance of the corn crop in the U.S., and reported economic losses in Mexico, this cyst nematode is given a moderate priority rating.

    CAB International. 2001. Punctodera chalcoensisin Crop protection compendium, global module, 3rd edition. Wallingford, UK: CAB International.
    Sosa Moss, C. 1987. Cyst nematodes in Mexico, Central America and South America. Nematologia Mediterranea 15:1-12.