Fall is in the air and harvest is starting up across Iowa. It has been noted soybean are holding onto their leaves. This green bean effect is more often thought of as green stems, however, this year there are more leaves and petioles staying green and attached to the main stem. Take note this occurrence may mean that soybean grain is drier than expected based on plant appearance. This green bean effect can be caused by both biotic (stink bugs, thrips, viruses, etc.) and abiotic (weather, late planting, fungicides, etc.).
Management to avoid green bean syndrome is difficult in-season because of variety of causes. At harvest, the best solution to green bean syndrome is to harvest fields when the soybean seeds are at the proper moisture content. Make sure the sickle bar on the combine is sharp and well-maintained. Slower harvest speeds will be needed to account for more soybean biomass coming through the combine.
Soybean at harvestable grain moisture with green (and yellow) leaves still attached. (photo credit: Rebecca Vittetoe)
Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Integrated Crop Management News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on October 3, 2022. The information contained within may not be the most current and accurate depending on when it is accessed.
- Associate Professor
- Extension Cropping Systems Specialist