March 7, 2008

A new fungicide, Proline®, from Bayer CropScience was registered in 2007. A triazole with prothioconazole as the active ingredient, Proline is labeled for suppression of Fusarium head blight (scab) as well as leaf rust, Septoria leaf and glume blotch, stem rust, and tan spot.

For suppression of Fusarium head blight, apply Proline from when 75% of wheat heads on the main stem are fully emerged (approximately Feekes growth stage 10.4) to when 50% of heads on the main stem are in flower (approximately Feekes 10.52), with optimal timing at 15% flower (approximately Feekes 10.51). Thorough coverage of wheat heads is essential to maximize suppression of Fusarium head blight. The rate for suppression is 4.3 to 5.7 fl oz/ac.

To control leaf diseases, Proline should be applied as a preventive spray or at first detection of disease symptoms at a rate of 4.3 to 5.0 fl oz/ac, with optimal timing aimed at protecting the flag leaf. A maximum of two sprays of Proline can be applied at a 14-day interval per year. The maximum amount that can be applied per year is 9.37 fl oz. Proline can be applied up to Feekes 10.52. The preharvest interval is 30 days.

Stephen Wegulo
Extension Plant Pathologist