Investigation on pathogenicity of Dilophospora alopecuri, cause of twist disease of wheat, in interaction with seed gall nematode (Anguina tritici)

Twist disease of wheat caused by Dilophospora alopecuri is one of the diseases that is observed along with wheat seed gall nematode (Anguina tritici) in Golestan province. In order to investigate the pathogenicity of the fungus, an experiment was performed in two cases including inoculation of the fungus alone, D. alopecuri and the nematode together and nematode alone on 4 cultivars of wheat known as Ehsan, Kouhdasht, Morvarid and Line 17 under greenhouse condition. Traits such as decrease of dry weight of infected plant, decrease of plant height, number of fungus-infected plants, number of spike infected by the fungus, number of nematode-infected plants, total weight of nematode galls, number of nematode galls and average galls weight per plant were measured in different cultivars. The analysis was performed using SAS software, and the comparison of the means was achieved by the LSD test. The results of analysis of variance showed that the interaction between D. alopecuri and wheat cultivars and the effect of the fungus on the measured indices in wheat cultivars was significant. The results showed that D. alopecuri can cause disease on wheat only in the presence of A. tritici and the presence of nematode is necessary for fungal pathogenicity and its distribution in the wheat spike.