The recommended timing for fungicide applications to suppress Fusarium head blight or scab is Feekes 10.5 in barley and Feekes 10.51 in wheat. At growth stage Feekes 10.5 the inflorescence or spike is completely emerged from the boot. Photo 1 shows the progress of the heading procres in barley. The third kulm is at Feekes 10.5 and the correct growth stage to receive a fungicide to suppress FHB. Photo 2 shows the progressing of the pollen shed in durum wheat; in the first kulm no anthers are visible on the outside of the individual florets, while in the second kulm the anthers are only visible in the center section of the spike. As these anthers are still yellow, they likely shed pollen earlier that day. In the third pollen shed is complete as anthers are visible across the length of the spike and are bleached and desiccated. The second photo closely approximates Feekes 10.51. The progression in spring and winter wheat is identical to the progression in durum wheat.
Note that not all varieties will extrude the anthers in which case anthers may not become visible on the outside despite the fact that pollen shed is complete. It is always a good idea to peel back the glumes in the center of the kulm and inspect the color or the anthers as you scout fields. If the anthers are yellow, pollen shed will likely commence that day.
Photo 1: The progression of the heading in six-row spring barley (photo courtesy of Joel Ransom, NDSU).
Photo 2: The progression of anthesis (pollenshed) in durum wheat (photo courtesy of Joel Ransom, NDSU).