Alyssa Koehler, Extension Field Crops Pathologist; akoehler@udel.edu
Figure 2. From left to right Feekes 10.3, Anthesis, Feekes 10.5.1 (yellow anthers beginning flowering), 4 days after anthesis (white anthers post flowering).
Across much of Sussex and Kent counties, wheat is now at flowering. In the Fusarium Risk Tool, our region remains at low risk (Figure 1). If you are planning for wheat fungicide application, yellow anthers in the center of the wheat head are the signal that you have reached Feekes 10.5.1. Once around 50% of heads are flowering, fungicides (Caramba, Miravis Ace, Prosaro) are most effective when applied within a 4-5 day window. Anthers can remain attached after flowering, but become a pale white (Figure 2). Fungicide products should be applied at the manufacturers recommended rate with nozzles that are angled 30-45° from horizontal (30 degrees is better than 45). Nozzles angled both forward and backward or twinjet nozzles that spray in two directions give better contact with the head and increase fungicide efficacy. For ground sprays, fungicides should be applied in at least 10-15 gallons of water per acre; aerial applications are recommended at 5 gallons per acre.
Figure 1. FHB Risk Model for May 13, 2021
Table 1: Fungicide Efficacy for Control of Wheat Diseases (CPN-3002-W)
