Because of its increasing frequency and intensity, head blight has been one of the most important diseases of winter cereal crops. Head blight causes both qualitative and quantitative losses. The ascospores formed on plant debris of many cultivated species are disseminated by the wind over long distances and can infect plant spikes through the anthers. The objectives of this research work were to quantify the air-borne inoculum of Gibberella zeae, the inoculum on the anthers, the disease intensity in the field, and the role of anthers in the infection process. The number of ascospores collected during wheat (Triticum aestivum) anthesis ranged from 6.6/cm².day in 1999 to 13.5/cm².day in 2000. At complete flowering, the infection by G. zeae reached 11.8% on loose anthers and 24.3% on those trapped. The environmental conditions that followed anthesis influenced disease development in the field. The trapped anthers played an important role in the disease epidemiology, and should be sprayed with fungicide to prevent spike infection after anthesis.
