The Mormon cricket plague may be finally coming to an end at least for this year. Nevada State Entomologist Jeff Knight says this year’s swarm is due to run its course by the end of July.
Knight gave an update to the Humboldt County Commission at their July 8 meeting. Knight said the insects have periodic outbreaks, which can last between three to five years. However, periodic outbreaks have lasted as long as 21 years, according to the handout Knight gave at the presentation. The entomologist said Nevada and Idaho are experiencing an outbreak. Besides Humboldt County, Knight said there are reports of outbreaks in Washoe County north of Reno, as well as Lander and Elko Counties.
The Nevada Department of Agriculture (NDA) has a program to spray and bait the insects but Knight said the process can take time. The program is a cooperative program between Plant Protection and Quarantine (PPQ), NDA and the Bureau of Land Management (BLM) and the US Forest Service (USFS). The agencies have a memorandum of understanding (MOU) in which those agencies request treatment and then NDA cooperate with PPQ in getting areas treated done and surveys of potential infestations completed in the early spring. Those surveys continue on through the summer and will be used to formulate the program’s strategy for battling the insect next year. “Basically,” Knight said, “we're recording where the egg laying is taking place then preparing those areas that we feel follow our priorities for treatment the next year.”
Knight said NDA sprayed in early June and have used bait since to control the insect. He also said the program has changed since the last major outbreak in 2003. “We don't have a giveaway program anymore,” he said. “There were a lot of problems with that. I've still got people with bags of bait in their garage from that [giveaway].” He also said there was a lot of misuse of the pesticide. “One of our biggest issues with the giveaway, people were not following the label and baiting BLM land and the private individual is not supposed to bait BLM land or public land.”
Knight told the Commission the program covers urban, cropland and public safety on roads. Dead insects can make roadways slick, causing vehicles to slide. Mormon crickets can also devastate cropland by feeding on plants or trampling plants from the weight of swarming insects. They feed on a variety of plant species including alfalfa, sweet clover, and vegetable gardens.
According to Knight, the insects hatch about early- to mid-March, developing into adults mid- to late June when they start laying eggs. Those eggs overwinter and then in some cases hatch the next year. He said there is data to suggest that these eggs may lay dormant in the ground for up to 11 years. The outbreaks such as what Nevada and Idaho are experiencing may be drought related, triggering the eggs to continue to develop and hatch the follow year.
Although Knight said the program will continue to bait areas through the end of July, this year’s cycle is coming to an end. “Their peak movement is about this time of year,” Knight said. “And from this point on, after mating starts and egg laying starts, the populations start dropping off. We should start seeing a decline very soon.”
To report Mormon crickets anywhere in the state, please provide as much detail about the infestation as possible using the Mormon cricket and grasshopper reporting form. The Mormon cricket and grasshopper reporting form is available at agri.nv.gov/entomology, or call the NDA Entomology Laboratory at (775) 353-3767.