Yields have been lower than expected for many of the first harvested fields. Heat during flowering and lack of rainfall may explain a large percentage of the loss. Disease and insect damage are also factors — large factors for some fields.
Growers may have to delay swathing or opt for straight combining on fields where not enough time has passed to allow for insecticide pre-harvest intervals.
Do your own disease survey. Just before or during harvest is a good time to survey fields to see how bad diseases really were. Checking stubble after swathing can work, too.