Evaluation of the susceptibility of various grass species to Gaeumannomyces graminis var. tritici.
Take-all, caused by the soil-borne pathogen Gaeumannomyces graminis var. tritici (Ggt), is a devastating root disease of wheat. As well as infected host residues from previous wheat crops, grass crop or weed species also play an important role in the carry-over of inoculum to the next wheat crop. However, the survival and spread of inoculum on different grasses differs considerably depending on their susceptibility to the pathogen. Using Triticum aestivum (wheat) and Avena sativa (oat) as susceptible and resistant standards, the susceptibility to Ggt of 24 grass species commonly found within wheat crops in New Zealand was examined in a simple laboratory assay. Of all the grass species evaluated, 83% were susceptible to Ggt with Bromus diandrus, Bromus willdenowii, Bromus inermis and Pennisetum clandestinum being highly susceptible, while Cynosurus cristatus, Cynodon dactylon and Paspalum dilatatum were highly resistant to the pathogen.