These are green stink bugs. Adults have a characteristic “shield” shape. There are several species of stink bugs but the most common in Africa is the green stink bug. Apart from soybean, the pest causes damage to more than 50 host plants.
Stink bugs feed on pods and seeds injecting toxins that affect seed germination, quality and may lead to pod distortion. The pods become shriveled and eventually detach from the plant. The seeds are discolored and have low oil content.
Scouting for stink bugs should begin when soybeans start at flowering and continue until maturity. More attention should be given to field edges to monitor entry of stink bugs into the field.
Broad-spectrum insecticides are generally effective and commonly used for stink bug management