Defoliation in soybean can be caused by insects (leaf eaters). Rarely does one insect pest cause major defoliation in Soybean. Generally, the soybean crop has a way of compensating for leaf loss. Thus the crop can loose a number of leaves without compromising yield. However, if leaf loss reaches more than 40% at vegetative stage and more than 20% at pod filling stage, and there is a pest which is actively feeding on the leaves, the farmer can apply recommended pesticides.
Leaf loss also happens in soybean at maturity. This is normal senescence.
Answers
Defoliation in soybean can be caused by insects (leaf eaters). Rarely does one insect pest cause major defoliation in Soybean. Generally, the soybean crop has a way of compensating for leaf loss. Thus the crop can loose a number of leaves without compromising yield. However, if leaf loss reaches more than 40% at vegetative stage and more than 20% at pod filling stage, and there is a pest which is actively feeding on the leaves, the farmer can apply recommended pesticides.
Leaf loss also happens in soybean at maturity. This is normal senescence.