Histopathological Changes Induced by Heterodera avenae Woll. in Roots of Winter Maize

Observations were made on the histopathological changes caused by Heterodera avenae pathotype Ha21 in winter maize. The nematode penetrated only 2–4 primary roots of maize cv. HPQM that became stubby. Nematodes entering near root cap developed to females and caused necrosis and death of meristematic tissue cells. Six to ten nematodes, when present near the root tip region, formed syncytia in the undifferentiated root tissues. Females developing posterior to the elongation zone in the cortex induced syncytia in the stelar region that contained 2–10 hypertrophied nuclei. Several second stage juveniles also invaded vascular bundles, formed syncytia which contained dense cytoplasm and 2–8 hypertrophied nuclei.