Pathotype, Resistance Classification, and Seed-Coating Control of Heterodera avenae and H. filipjevi in the North China Plain.

Heterodera avenae and H. filipjevi are cereal cyst nematodes (CCNs) that infect cereals in 16 provinces of China. CCN populations from Xuchang, Tangyin, Qihe, and Juye were tested using 23 barley, oat, and wheat entries of the International Test Assortment for Defining Cereal Cyst Nematode Pathotypes. H. avenae populations from Tangyin, Qihe, and Juye were classified as pathotype Ha91, and H. filipjevi from Xuchang was classified as a new pathotype similar to pathotype West. Among 42 other winter wheat cultivars, 29 and 30 were differentially susceptible, 13 and 12 were differentially resistant to H. avenae and H. filipjevi, respectively. Three entries were resistant to both species, and three other entries were resistant to H. avenae and moderately resistant to H. filipjevi. Coating wheat seed with abamectin + isopycnic imidacloprid or methylene (bis) thiocyanate + thiamethoxam reduced the number of H. avenae and H. filipjevi cysts by 46 to 56%, increased wheat yield by 9 to 27%, and improved net income by 660 to 2,640 Chinese Yuan ha-1, respectively. Resistant wheat cultivars are scarce in China, and seed coating is considered the most suitable method for controlling CCNs in the North China Plain, where crop rotation cannot be practiced.