Occurrence and Development of the Cereal Cyst Nematode (Heterodera avenae) in Shandong, China

The cereal cyst nematode (CCN), Heterodera aveane, has been found in 16 provinces of China, including the Shandong winter-wheat-growing region. This study investigated the population dynamics of H. avenae in the winter wheat ‘Jimai 22’ and ‘Tainong 18’ for two consecutive years in the field. Soil and root samples were collected during the winter-wheat-growing season and H. avenae population densities and life-stages determined. H. avenae population dynamics in roots and soil of the two winter wheat cultivars were similar over the 2-year period. Second-stage juvenile (J2) population densities in wheat roots were greatest during booting stage (April), when mean soil temperature was between 11.8 and 14.4°C. Cysts in rhizosphere soil increased significantly when new cysts were formed after Zadoks (Z) 47 (booting stage). There was a peak in J2 population densities in soil during Z23 and Z30 (tillering and stem elongation, respectively) whereas J2 population densities were the lowest at Z13 (seedling stage). This research provides important information indicating that J2 populations in roots and soil increased after the wheat winter dormancy period. Knowledge of when different life stages of H. avenae occur in winter wheat in Shandong will provide valuable insights to enable the development of an integrated approach to manage this plant-parasitic nematode.