“Coulda, woulda, shoulda syndrome.” Harvest time is often when crop producers can self analyze if they are infected with this decision malady. Generally, they are aware of a particular challenge to a growing crop so a corrective action could have been taken to address the concern at hand. Farmers who experience the syndrome probably would have taken action had they ventured far enough into the fields in question to accurately assess the potential yield threat posed by pests lurking in the host crop. Realizing that action should have taken place often comes about during the harvest process.

Several area farmers have noted how ugly soybeans look as they fill combine bins or when trucks and wagons are loaded. “Did spider mites have something to do with the ugly beans?” was a question posed. Although severely-invested mite areas may have stressed soybean plants enough to severely limit yield and contribute to tiny and even shriveled soybeans in a grain sample, the majority of ugliness is likely due to insect invaders who feed directly on pods. Bean leaf beetles, grasshoppers and stink bugs are all capable of inflicting damage to the soybean grain during the pod fill stage of development.  

While fields vary, the most likely culprit to soybean pod feeding was the bean leaf beetle. As leaves lost their color, the BLB sought more succulent food and began chewing on soybean pods. Sometimes the insects would only scrape off the green tissue in the pods, but did not chew through the pod wall. However, this scarring may have provided an opening for entry of spores of various fungal diseases normally blocked by the pod surface. Seed staining may be the result of mild feeding, a total seed contamination may be seen from severe feeding situations.  

Marauding grasshoppers would have more likely have caused direct injury to the soybean seed itself. Strong mouthparts allow the insects to chew directly through the pod wall, taking bites out of the seed or even devouring seeds completely.  

Finally, the most important insect pod feeder may be the stink bug. We have heard more about stink bugs this year due to new species like the brown marmorated stink bug. These smelly critters feed directly on pods and seeds, but the injury caused can be difficult to assess because their mouthparts leave no obvious feeding scars. Pods are penetrated by puncturing mouthparts. Digestive enzymes are injected into the seeds and the feeding provides an avenue for disease organisms to gain entry as well.  

Harvest time analysis may show that more and timely applications of insect control products could have boosted yields and improved soybean quality. However, do not jump to the conclusion that preventative applications are the “cure all” to prevent such yield and quality damage in future crops. Economic thresholds are established annually by Extension entomologists to help determine when corrective actions are necessary. The rapid upward movement of this year’s soybean market required threshold adjustments. In 2012, some farmers kept up with the changing scene and made timely insecticide applications, some did not. Others mistakenly utilized products too aggressively, knocking out beneficial insects, resulting in additional treatments being needed to control new infestations of pod feeding pests. 

As harvest progresses, yield monitors and grain samples will reveal how the corn and soybean crops might have benefited from more timely management decisions. Maintaining good records of yields and quality of grain from different fields, or even areas within fields can help farmers avoid economic loss due to the “coulda, woulda, shoulda syndrome.”