If you’ve watched any Denver area news channels lately, or read any number of statewide news publications, you’ve seen that there is a lot of coverage on grasshoppers being seen in devastating numbers across our state. However, it is now late July and this is the first article in the Pilot to address grasshoppers in 2024. As the past two summers have seen extensive coverage of this topic in these pages, what happened that grasshoppers haven’t been part of recent local news?

In late summer 2023, the prospects of a heavy population in summer 2024 was strong. How do we know this? Every summer the U.S. Department of Agriculture counts grasshoppers starting early in the spring and then throughout the summer until a killing frost occurs. 

The first counts, which focus on grasshopper young or nymphs, helps predict whether or not control efforts will be needed that growing season. In mid-to-late summer, surviving adults are counted to get an idea of how many eggs will be laid and provide a glimpse into what numbers of grasshoppers may hatch as the eggs come out of dormancy the next spring. Maps with forecasts are then created for the next growing season to allow land managers to prepare for grasshoppers if need be.

The prediction for 2024 was that Routt County would continue to see large numbers of grasshopper hatches based on egg laying in late summer 2023. The numbers were predicted to be significant enough that the Routt County Commissioners decided in early 2024 to set aside Taylor Grazing Act monies to continue a grasshopper spraying reimbursement program which subsidizes control efforts on properties over 35 acres. But the large numbers predicted have yet to be seen in most areas. Why?

A late spring and strong rains in June have proved thus far to be very effective for grasshopper control. Many of the nymphs observed hatching in mid-June were effectively “drowned out” and/or decimated by locally heavy rains and small, but impactful hailstorms. Cooler temperatures, including evenings that were down to the mid-30s, impacted delicate nymphs, too, who don’t have the capacity to survive less-than-ideal conditions. Significantly reduced numbers of nymphs means, of course, that we are seeing many fewer adults than predicted, and will likely mean less eggs will be laid this summer, improving our outlook for summer 2025.

We are not out of the woods yet, however. While early hatches were impacted by the weather, some species of grasshoppers simply didn’t hatch due to the cooler and wetter June. That means that in some areas of Northwest Colorado, grasshoppers are still just hatching. Recent USDA surveys indicate that some grasshoppers are just in their third, second or even first instars, much later than we typically see. This means control efforts may still need to take place in some areas and landowners should remain vigilant in seeing what numbers look like on their properties. 

If you have questions about whether or not you should engage in grasshopper control efforts this year, or if you have conducted control efforts over a large acreage and want to participate in the $2/acre reimbursement program being offered in Routt County, contact the CSU Extension office by emailing thagenbuch@co.routt.co.us or call 970-879-0825.

Todd Hagenbuch is the Ag/Natural Resources Extension Specialist for Colorado State University in Routt County.