Proline Fungicide Available For Wheat Scab
With wheat prices hovering around $8.00 per bushel, management practices that will help maintain wheat yields and wheat quality are critical in 2008. Last year the weather was conducive to significant disease infection in southeast Nebraska. With good prices in 2007, several producers decided to treat wheat fields with fungicides. Wheat rust was a problem, especially for some susceptible varieties. Farmers that used fungicides on wheat varieties susceptible to rust saw a significant yield increase, (20 bu/ac) compared to similar untreated wheat varieties. Due to the wet conditions we experienced last spring, there were a number of fields of wheat that were infected with wheat scab (Fusarium head blight). Unfortunately we did not have any effective wheat fungicides available to treat for wheat scab in 2007. This decreased yields and wheat quality significantly in infected fields.
Later in 2007, a new fungicide, Proline was registered. It is a triazole and is labeled for suppression of Fusarium head blight (scab) as well as leaf rust, Septoria leaf glume blotch, stem rust and tan spot. This is good news because now there is a product available to Nebraska producers for use on wheat scab. For suppression of wheat scab, apply Proline from when 75% of wheat heads on the main stem are fully emerged (Feekes growth stage 10.4) to when 50% of heads on the main stem are in flower (Feekes 10.52).
Wheat scab infects the wheat head during flowering, so this is when treatment it required. Wheat scab survives in soil or stubble of host crops such as corn, wheat or grass. It is more of a problem in reduced till or no-till environments and in wheat following corn. If we have wet weather, spores are produced, carried by air currents and infect wheat heads during flowering.
For protection against other diseases, such as leaf rust, Septoria leaf and glume blotch or tan spot, timing of fungicide is to protect the flag leaf. Proline can be applied as a preventive spray or at first detection of disease symptoms. There are also other fungicides that can be used for these diseases as well. Proline can be applied up to Feekes 10.52 (flowering complete to top of spike) and there is a preharvest interval of 30 days.
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