This fall soybean harvest in some fields was complicated by immature, green plants scattered across the field while most of the plants were ready to cut. These green plants slowed harvest because they were difficult to cut, and some growers may have been docked at the elevator because of green seed. The green plants varied in maturity. Some had green pods with normally developing seed while others had tufts of small immature pods and a few pods with a single large seed and some plants had a mixture of these pod types. This problem occurred across the state on a wide number of cultivars and soil types but was worse in June-planted fields. In most fields, less than one percent of the plants were affected, but the problem looked much worse because the green plants were so visible. Yield losses in these fields were probably negligible, however in some fields or in parts of fields, a much higher proportion of plants were affected, likely lowering yields.
At this time, we can’t say what caused this problem, but the environment, diseases, or stink bugs could be involved. The high temperatures at flowering this year may have led to uneven pollination and flower abortion, forcing the plants to reflower delaying pod set and maturity. There are a number of viruses and phytoplasmas (pathogens related to bacteria) that can keep soybean plants from maturing. Tests are currently being conducted on affected plants for these pathogens. Stink bug feeding can cause a number of pod and seed problems resulting in plants that fail to mature. Soybeans that fail to mature occur every year somewhere in Arkansas, but usually not in the same field the following year. This has made determining the cause or causes of this problem difficult but also means that just because the problem occurred this year doesn’t mean it will be a problem next year. At this point there are no recommended control measures for delayed maturity but encouraging adequate pollination by preventing plant stress at flowering and controlling stink bugs are good crop management practices and may be helpful.