RBC | Rural living comes with the cost of dealing with Mother Nature, sometimes at her worst: high winds, big snows, drought, forest fires, flooding and on occasion, really ugly insects. And Mormon crickets are among the ugliest of them all. These creatures have been increasing in numbers over the past five years or so and 2023 has proven to be a “perfect storm” for these creatures.
Residents along County Rd. 7 (Strawberry Creek) are among those most impacted by the migration of this year’s batch of Anabrus simplex, aka Mormon crickets, causing slick roadways, among other problems. According to Moffat County Weed and Pest Director Jesse Schroeder, the 2023 hatch appears to be as much as 10 times greater than in previous years. NANCY RICHARDSON PHOTO
Why have Mormon crickets been so bad this year?
Here are the theories that are being discussed:
First of all, Mormon cricket populations are cyclic, and numbers have been increasing in recent years in a similar manner to what happened in the late 1990’s when the number of acres infested with Mormon crickets in Utah rose from 1,180 acres in 1997 to 2,450,650 by 2002 (see Table). This kind of population increase without a natural (fire, flood, freeze) or man-made response hits a point where it just explodes like we have seen this year. According to Jesse Schroeder from Moffat County Weed and Pest Management the hatch-out this year appears to be 10 times greater than in previous years.
This may be due to the heavy snow cover that we had all of last winter which insulated the ground and protected it from a hard freeze. A hard ground freeze might have killed, or at least reduced, the number of surviving eggs.
The next factors to consider are: The ground temperature needs to be at least 40oF for the eggs to hatch, so this year the Mormon crickets started to hatch out in April as usual in bare ground areas, but in Rio Blanco County, the big numbers weren’t seen until June. This means the environmental conditions were all just perfect for the nymphs to survive. There was the right amount of moisture, there were no below-freezing nights to kill the newborn nymphs, and there was an abundance of wildflowers and hayfields to provide food. In other years, in the absence of these favorable conditions, Mormon crickets would have been prone to eat each other. They are incredibly cannibalistic and will readily eat their family members in order to survive.
Mormon crickets have many natural enemies that play an important part in keeping them in check. Eggs are destroyed by some species of parasitic wasps and flies, and the larvae of many predatory insects. Nymphs and adults are preyed upon by many animals including game birds, hawks, sea gulls, wasps, ground beetles and robber flies. Diseases can also keep populations down. These factors didn’t seem to happen this year in big enough numbers to make an impact.
So, not only was there an extremely successful hatch-out, there was also an extremely high survival rate. This combination gave us a perfect storm.
How long are they going to stay?
How long a swarm of Mormon crickets may stay at any one location varies depending on whether they are in “Marching Mode” or in “Eating Mode.” In some locations in Rio Blanco County, crickets virtually covered an entire yard one day, were greatly reduced the second day and were mostly gone by the third day. At other locations with fields of alfalfa, sainfoin or other crops attractive to Mormon crickets, the residents were not so lucky and lost entire crops or entire cuttings and had swarms stick around for extended periods. There is no magic number, but the literature says they usually stay three to four days, move on together and cover ½ to 1 mile a day and go 25 to 50 miles per season.
In general, Mormon crickets have a migratory habit. In Rio Blanco County, they seem to move in a generally east–southeast direction. This seems to have something to do with maintaining their preferred temperature throughout the day. In the morning they are seeking the warmth of the sun, and will move when temperatures are between 65oF and 95oF. As it gets hotter, they will seek shelter under plants, cow pies, or other shade. Often times they get into the hay windrows or unbaled hay and end up costing ranchers a significant amount of crop loss.
So What Now?
The Mormon crickets are starting to lay their eggs now, but they can continue to do this for the next month or even two before they are done for the season. But it does mark the beginning of the end. Unfortunately, there is no easy fix. There is no golden rainbow at the end of this story. The Weed and Pest Department is hoping to get more county-sponsored bait back in stock soon, but it will be in limited supply due to shortages from the warehouse. There was no way to have predicted this enormous outbreak and there is no state or federal response planned for this year.
You can call Linda Masters at the Extension Office 970-878-9494. We do not give away or sell chemicals, but we might have solutions for small scale issues. For example, if you have a small garden, run some chicken wire around it and cover it with tightly stretched plastic material (Visqueen or trash bags will work). Mormon crickets cannot fly, they only hop and not more than three-feet high. They cannot crawl up slippery materials like slick plastic.
If you have had Mormon crickets in your yard this year, go out and rake your yard and disturb the soil before winter. If the crickets have laid eggs in your yard you want the eggs on top of the soil so that they freeze this coming winter. No need to rototill, just rake, the eggs are less than an inch deep.
Public meetings to develop a plan for mitigation next year are planned this fall. Residents who have been affected are urged to watch for and participate in those meetings.
For more information on Mormon crickets, visit:
https://www.uwyo.edu/entomology/grasshoppers/field-guide/ansi.html
https://extension.unr.edu/publication.aspx?PubID=2346
BY LINDA MASTERS | Special to the Herald Times
