In spite of a relatively slow start due of cool, wet conditions, the wheat crop has developed well and is now between the jointing (in the north) and boot (in the south) growth stages. At this rate of development, and with warmer weather in the forecast, flowering should begin within the next 10 to 20 days. More rain is also forecasted for later this week and early next week (May 13-18). Rain + warmer weather + wheat flowering = increased risk for head scab and vomitoxin. Early flowering fields in southern Ohio may be at risk within the next week or so and growers in those areas should be prepared to apply a fungicide at flowering to suppress scab. However, with flowering still several days away, things could change quickly, either increasing or decreasing the risk of scab. So, keep your eyes on the weather and the forecasting system as we approach flowering.

In the meantime, remember, the wet conditions we have had so far this season and temperatures in the 60s and 70s for the next several days are also favorable for foliar diseases such as powdery mildew, Septoria, and Stagonospora blotch. Powdery mildew and Septoria are already very prevalent in some locations. Continue to scout your fields and be prepared to apply a fungicide to prevent these diseases from spreading and reaching the flag leaf, especially if your variety is susceptible and conditions continue to be favorable (wet and humid). Damage to the flag leaf caused by foliar diseases could result in reduced grain yield and quality. A foliar fungicide application between flag leaf emergence and heading usually provides the best control of these diseases; however, this relatively early application WILL NOT provide adequate protection against scab and vomitoxin if favorable conditions occur during flowering and early grain fill. Fungicide application for scab and vomitoxin suppression MUST be made at flowering.

An updated fungicide efficacy chart with a list of products labeled for wheat, efficacy against foliar and head diseases, application rates, and pre-harvest intervals can be found on the field crops diseases Web site.