Source: NCSU COLLEGE OF AG & LIFE SCIENCES, 11/2/19


We are getting widespread reports of green stem in Eastern North Carolina this Fall (2019). We are most frequently getting reports of the issue from maturity groups mid-IV to mid-V, although we know green stem can impact a wider range of maturity groups. Do we have all the answers about this phenomenon? No. The causes are largely unknown but attributed to various stressors during pod and seed development. Knowing that this has been a frequently discussed issue over the past few years, we wanted to discuss some information on green stem. 

What is green stem? Green stem is a term for a soybean plant with non-normal senescence resulting in the stem remaining green (and sometimes retaining leaves) when generally other parts of the plant have senesced (most leaves have dropped, pods and seed are mature). See photo below provided by Lenoir County Extension Agent Steve Killette in 2019. 

What causes green stem?  There is no clear cause of green stem. The problem can vary from year-to-year and variety-to-variety. It is not uncommon for us to get a report on green stem that has showed up in one variety planted on the same day or a couple weeks earlier/later than the same variety down the road that does not have green stem. 

The following factors have been previously implicated for causing green stem: stink bugs (and other insects), viruses and other diseases; however, previous USDA research shows that green stem can be present without any of these biotic factors present (Mueller, 2013). Nutrient deficiencies and ultra high or low soybean populations have also been reported to potentially contribute to the issue.

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