Anatomical Changes Induced by Punctodera chalcoensis in Corn Roots.

Punctodera chalcoensis Stone et al. is a cyst nematode parasitizing corn (Zea mays L.) and teosinte (Zea mexicana (Schrad.) Kuntz) in Mexico (7). This nematode damages corn severely in Tlaxcala and Puebla states of Mexico (7). Pathogenic studies of P. chalcoensis on corn have been conducted in the greenhouse (2). Mundo-Ocampo and Baldwin (6) reported that P. chalcoensis induces a syncytium in roots. These authors sugges ted that Globodera, Heterodera, and Punctodera evolved from a common ancestor, in part because species in these genera induce similar syncytia. However, no description is given of the anatomical changes induced by P. chalcoensis, nor is the plant host mentioned. We studied the anatomical alterations induced by P. chalcoensis on corn (Zea mays cv. Criollo Chalquefio) roots. Corn roots infected with P. chalcoensis were collected from a field in Amecameca, Mexico. Roots were gently washed free of soil, cut in 4 -