Understanding green stem in soybeans

August 29, 2025

Example of green stem on fully developed soybean plants.

Green stem is a term that describes abnormal patterns of maturation in soybean, where the seeds and pods mature fully even though the stems stay green. A new diagnostic guide describes the symptoms of green stem, field conditions that may increase green stem risk, and management options for fields with widespread green stem occurrence.

Earn 1 CEU in Crop Management by reading the article and then taking the quiz.

1. Which of the following best describes “green stem” in soybeans?
a. A fungal disease that prevents pods from maturing.
b. A viral disease where pods mature earlier than normal and stems turn from brown to green.
c. A delayed or abnormal senescence pattern affecting stems but not pods.
d. A nutrient deficiency symptom caused by low potassium.

2. In the United States, green stem is generally more prevalent in
a. northern soybean-growing states.
b. southern soybean-growing states.
c. only irrigated soybean systems.
d. areas with sandy soils.

3. According to survey data cited in the article, approximately what percentage of farmers and crop advisers reported observing delayed maturation and/or green stem symptoms in 2014-2015?
a. 25%.
b. 50%.
c. Over 77%.
d. Over 90%.

4. Which growth stage is considered most critical for environmental stress to increase green stem severity?
a. R3 (beginning pod).
b. R4 (full pod).
c. R5 (beginning seed fill).
d. R8 (full maturity).

5. Which insect pest has been associated with green stem through feeding damage rather than viral transmission?
a. Cerotoma trifurcata (bean leaf beetle).
b. Nezara viridula (southern green stink bug).
c. Orosius orientalis (common brown leafhopper).
d. Riptortus pedestris (bean bug).

6. Which of the following is NOT listed as a potential management option for green stem?
a. Reducing combine speed during harvest.
b. Waiting for a hard frost.
c. Applying nitrogen fertilizer at R6–R7 to accelerate senescence.
d. Applying desiccants prior to harvest.

7. Green stem typically causes significant yield loss in soybeans.

a. True.

b. False.

8. Which factor in soybean-breeding programs has been associated with higher green stem sensitivity?
a. Low chlorophyll concentration in stems.
b. High vegetative storage protein accumulation.
c. Increased pod-shattering tendency.
d. High seed protein content.

9. Fungicide-induced “stay green” effects are the same as green stem.
a. True.

b. False.

10. Which of the following seed quality impacts has been linked to green stem?
a. Higher oil content and smaller seed size.
b. Increased protein content and improved germination.
c. Larger seed size, lower fat ratio, and reduced germination.
d. No measurable effect on seed composition.

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