ABSTRACT
Tan spot of wheat, caused by the fungus Pyrenophora tritici-repentis, anamorphic form Drechslera tritici-repentis, is one of the major diseases affecting this crop. The lesion expansion is an important component of this epidemic and, similarly to others, can be influenced by temperature. Therefore, the aim of this study was to evaluate the effect of temperature on the expansion and number of lesions, as well as on the severity of tan spot of wheat. The study was conducted in climatic chambers at five temperatures (10, 15, 20, 25 and 30°C) with the cultivars Mirante and Fundacep Horizonte. Plants were inoculated, in the stage of three expanded leaves, with 3x103conidia/ml suspension in water. The lesions were measured at every three days from the onset of symptoms. In addition, lesions were counted per leaf and severity scores were estimated. The adopted design was in randomized block with four replicates, and each pot constituted a replicate. Temperature positively influenced the disease increase, and at 30°C the number and progress of lesions, as well as the severity of the disease, were greater.
Additional key-words:
epidemic components; Drechslera tritici-repentis; Triticum aestivum
