The reasoning behind that is that we are seeing the pod splitting in different maturity groups as well as different varieties. I attribute the problem to Mother Nature. She is an easy scapegoat, but this is one situation where there is no doubt about what is causing the problems. With all of the variable weather patterns that we are experiencing across the state, some of our beans have been extremely dry when pod initiation and pod set were beginning. The crop had also been dry for weeks in some cases before R1. With these types of growing conditions, the plant certainly does not know when the next rain is coming, and pods are set initially somewhat smaller than they “normally” should be. If the crop is irrigated or if we get a soaking rain during seed fill-in, which in many situations we have, pod-splitting problems can develop.
The reason for pods splitting seems to be that beans begin to fill and essentially fill too fast for the pod’s capacity, which leads to splitting. After the pods are split, diseases and insects set in and destroy the exposed seed in addition to possibly affecting the good seeds. You also run the risk of seed sprouting in the pod when you have splits. How much yield loss can be expected? This is very difficult to answer. Each field is different and has to be handled differently. In most of the fields where I have seen the splitting, I estimate at least a 5 percent yield loss based on seed loss alone. This is not accounting for damage by insects or diseases. The worst that I have seen is about 10 percent, which is significant when we are struggling to make a crop, especially on our later-planted beans.
There are not many options for producers when they find splitting pods in their fields. It really cannot be prevented, but some varieties do handle the adverse growing conditions better than others. It is difficult for a seed company to evaluate for this trait because you would have to reproduce non-conducive growing conditions in the field, and this is unrealistic. As I mentioned, each field has to be treated differently. We do have harvest aids available including sodium chlorate, Paraquat and now Aim. The use of harvest aids may be warranted where beans are lodging and really need to be harvested before mechanical harvest is not feasible. Otherwise, applying a harvest aid will definitely dry out the pods even more, which could cause premature shattering when the cutter bar hit the stalks.
On another note, there is positive news. We have harvested about 5 percent to 10 percent of the crop and early numbers are very encouraging. Most Group IV reports that I have received are ranging from 35 to 58 bushels per acre.
David Lanclos is Extension corn and soybean specialist with the LSU AgCenter.