In recent years Ohio has seen a huge resurgence of rye usage as a cover crop. While rye can be a good option as a cover crop, it is also a persistent threat as a weed in subsequent crops and neighboring fields. In parts of Ohio this season, volunteer rye is obvious in many crop fields. This is usually a minor threat to the crop, but in certain circumstances, it does create big problems.
The problem of volunteer rye tends to become a more serious issue when seed drifts into a neighboring field belonging to another producer. Neighbors often resent seeing what is in effect a weed that was scattered (all be it accidentally) on their field. The issue can grow exponentially if the neighboring field happens to be a seed production field of wheat where any rye (even one plant) is unacceptable.
Even in regular fields of wheat, volunteer rye can become an economic problem if the concentration is high enough. If rye is found in a sample of wheat, it will typically be treated as foreign material. As such, any foreign material above 1% is typically subtracted from the gross weight and can be subject to other discounts as well.
Any crop growing in the wrong place can become a weed. Rye has many properties that make it a good cover crop, but its ability to germinate with little cover and its persistence makes it a formattable weed as well. Keep that in mind when seeding cover crops and avoid seeding rye by aircraft in sensitive areas such as seed production fields.