Conditions have been nearly perfect this summer for grasshoppers in St Louis County. They thrive in hot dry conditions due to rain and moist conditions causing conditions to favor growth and reproduction. One aspect of the grasshopper that is critical is grasshoppers only have one cycle per year. The population suggested that their population is cyclical and as you recall last summer was also drier than normal and allowed the population to persist and lay a higher than a normal number of eggs. This coupled with perfect conditions this summer has created the perfect storm.
Moisture is a natural enemy via causing a fungal disease in the young grasshoppers reducing the numbers that make it to maturity and lay eggs. Another natural enemy is the Blister Beetle. These are great for keeping the population down, but as Grasshopper numbers go up the Blister Beetle numbers also go up. This seems like a good situation, but if horses consume these beetles, it can kill the horse. (I will do another post shortly about the Blister Beetle)
In the home garden and lawn, you have a few organic and no organic options for control and I would suggest checking out the attached publication for more details.
In farm fields, I suggest using an Integrated Pest Management (IPM) approach to determine when to control them. One thing with Grasshoppers is that they are a hungry bunch and we reach threshold levels very quickly. I have seen many fields which are requiring treatment based on IPM and economic thresholds. These are also addressed in the referenced publication.
Please let me know if you have further questions about this or other Agriculture, Horticulture or Natural Resource topics.