From heading to flowering is when wheat is susceptible to the wheat midge. Once flowering is complete wheat midge no longer attack the developing heads. Wheat midge is not a problem on barley. Flowering is also when wheat is most susceptible to scab infection. Barley flowers in the boot and is most susceptible to scab once heading occurs.
Monitoring heading in barley and wheat is extremely critical for effective control of either pest.
The time required for both wheat and barley to go from mid boot to head emergence can range from three to five days. Obviously environmental conditions have a large impact on the developmental rate. Warm sunny days favor rapid development. Both wheat and barley will require about 140 GDD to go from mid boot to heading. Wheat will require about 270 GDD to go from mid boot to completion of flowering.