Threatening insect and disease pests to wheat
Wheat growers are encouraged to scout now for rust diseases, armyworms and cereal leaf beetles.
This has been a strange year for wheat and it’s clear that the surprises are not over. While the crop is not expected to be a bin buster, it is as important as ever to avoid being ambushed by various pests as the crop attempts to develop and fill grain heads.
Perhaps most notable in the past 10 days is the confirmation of striped rust in central Michigan. This is a relatively new disease to the state, but it can be said from experience that it can seriously reduce grain yields. It is also somewhat alarming that it is coming onto the scene already during May as it is usually found well after flowering. More about the disease and photos can be found in Identifying rust diseases of wheat and barley by Erik DeWolf et. al.
Additional diseases currently being found include the rust more common to Michigan, leaf rust. In addition, leaf spots and powdery mildew are present in many wheat fields. Fusarium head scab is a disease that is perennially a concern of the industry at the time of heading. However, the national forecasting model suggests the state is at a relatively low risk status based on past and current weather conditions.
All wheat growers should visit there fields now to see what might be developing. Where wheat is past the time of initial flowering and a fungicide has not been applied, growers might consider applying one now if rusts or an abundance of leaf spots or powdery mildew are present. There is still time to apply a fungicide as the pre-harvest interval for Prosaro, Caramba and tebuconazole is 30 days (there is generally six weeks or more between the time of early flowering and harvest). Prior to applying a fungicide, also take stock of insect pest numbers including armyworm and cereal leaf beetle.