SEM Observations and Morphometrics of the Cabbage Cyst Nematode, Heterodera cruciferae Franklin, 1945, Collected Where Brassica spp. Are Grown in Tabriz, Iran

摘要

During a survey of plant parasitic nematode biodiversity in vegetable fields of Tabriz, East Azerbaijan province, Iran between 2004 and 2005, 25 species belonging to 16 genera of nematodes were identified from 88 soil and root samples, among which a large population of the cyst nematode, Heterodera cruciferae, was found in most of the sampling regions. Cysts, males, and second-stage juveniles were extracted from field soils, and from the infected roots of kohlrabi (Brassica oleracea L. var. gongylodes) and white cabbage (Brassica oleracea L. var. captita alba). The morphology of the cysts, second-stage juveniles, and males established the identity of Heterodera cruciferae Franklin, 1945. Morphological characters used for accurate identification included cyst shape, characteristics of the cyst terminal cone, including the nature of fenestration, and cyst wall pattern. Second-stage juvenile characters critical to the identification were body and stylet length, shape of stylet knobs, and shape and length of the tail and tail terminus; for males the important characters were stylet and spicule length. Comparison to other closely related species is also presented. Photomicrographs and SEM images of external and internal parts of the cysts are shown. This is a new record for H. cruciferae on cabbage in Iran.