24 April 2025

Identifying leaf three in winter wheat crops

Some 80% of the yield from winter wheat comes from the top half of the canopy, so having a good clean foundation is important. One of the key ways of achieving this is ensuring the optimum timing of fungicide applications.

Current fungicide choices do not have the flexibility that they used to have a number of years ago, so timing on the application of different fungicides needs to be precise. Growth stage may not be an accurate indicator of the actual leaves present in the crop, so dissecting plants and identifying the correct leaf to apply the fungicide is critical for optimum performance.

Leaf three on many winter wheat crops will be fully emerged this week, so it is the optimum time for T1 (leaf 3) fungicide applications to control septoria. If you are unsure if leaf 3 is full emerged, dissect the plants and count the leaves starting with the flag leaf (leaf 1).

In the video below, Teagasc Crops Specialist, Shay Phelan and Steven Kildea, Teagasc Oak Park, highlight how to identify leaf 3 and its importance for the timing of the first fungicide:

More from Teagasc Daily: Tillage advice: PGRs, fungicides and weed control