Rhizobia nodules
Rhizobia, a type of root -- colonizing bacteria that supply nitrogen to legumes, reside in protective nodules formed by the plant. The bright red color of the opened nodule is an indication of healthy rhizobia inside.
soy/aphid/nodule collage
Soybean plants interact with many different organisms in the field. Soybean aphids (upper inset) are invasive insect pests of the above ground portion of the plant, while nitrogen-fixing bacteria (lower inset) colonize the roots inside nodules and provide the plant with much needed nitrogen
Soybean Aphid
Soybean aphids are a recently introduced pest to the U.S., causing yield losses and increased insecticide sprays. The aphids feed on the sap of soybean plants.
Soybean Field
Soybean field at the Penn State Russell E. Larson Agricultural Research farm at Rock Springs, Pa.
![A group photo of the ECOGIG team aboard the "Jewels of the Gulf: Deepwater Expedition."](https://news.psu.edu/sites/default/files/styles/multimedia_most_popular/public/jewels-of-the-gulf-team-shot.jpg?itok=StIJuEKt ""Jewels of the Gulf: Deepwater Expedition" Group Shot")