Mormon crickets (Anabrus simplex) are not true crickets but large, flightless shield-backed katydids native to the western United States. These insects are notorious for their highly destructive migratory behavior, forming massive, marching bands that can span miles and number in the millions. Outbreaks can last for years, causing significant economic damage to rangeland and cultivated crops by consuming nearly all vegetation. Due to their voracious appetites and high mobility, effective control methods are necessary to protect property and limit the spread of an infestation.
Physical Barriers and Immediate Removal Techniques
Homeowners can employ mechanical and physical methods to protect localized areas like gardens or residential structures. Since Mormon crickets are incapable of flight, smooth, vertical barriers are an effective deterrent against property invasion. Creating a cricket fence using materials like slick metal flashing or heavy-duty plastic sheeting, sealed tightly to the ground, can prevent them from climbing over or crawling under the barrier. The material should be at least 18 to 24 inches high to be effective, forcing the crickets to migrate around the protected area.
Trenching is highly effective, often used with slick barriers to trap insects during migration. A trench dug with steep sides, sometimes V-shaped, can be lined with a smooth material like plastic to prevent the crickets from escaping. Pits or traps should be dug at intervals along the barrier or trench line to collect the insects. These measures must be continuously monitored because a migrating band can quickly fill a trench or overwhelm a barrier, allowing subsequent crickets to cross over the bodies of their trapped counterparts.
For smaller, localized groups that have already breached a perimeter or invaded a porch, immediate physical destruction methods are practical. Crushing small clusters is an option, although the resulting fluids can attract other crickets due to their cannibalistic nature. An efficient, clean method for removing crickets from structures or small areas is using a shop vacuum equipped with a disposable bag, which can then be sealed and discarded.
Utilizing Targeted Baits and Chemical Treatments
Chemical control often focuses on targeted baiting strategies that leverage the species’ natural behaviors. The most effective chemical for homeowner use is a bran-based bait containing the insecticide carbaryl. When applied, this bait attracts crickets, and once ingested, the carbaryl acts as a stomach poison.
The effectiveness of carbaryl bait is significantly amplified by the crickets’ opportunistic cannibalism. When a poisoned cricket dies, other crickets consume its body, resulting in a secondary kill effect as the toxin passes through the population. This mechanism allows a single application to kill multiple insects, making it a highly efficient strategy. Baits should be broadcast around the perimeter of the property or directly into the path of an approaching band to intercept the migration.
For professional or large-scale efforts, insect growth regulators (IGRs) like diflubenzuron are used, primarily against younger nymphal stages. Diflubenzuron works by interfering with the molting process, preventing nymphs from developing their new exoskeleton. Since this chemical only affects molting insects, it is applied early in the season when the population consists of vulnerable nymphs. While baiting is the primary method for swarm control, residual perimeter treatments, such as liquid or dust applications of broad-spectrum insecticides, can be used as a secondary defense to protect individual structures.
Coordinated Management for Mass Infestations
Individual control methods are often insufficient for the vast scale of a Mormon cricket mass infestation, necessitating a coordinated, regional approach. When large bands are spotted, reporting the location to local agriculture or pest management officials, such as the state department of agriculture, is the first step. These governmental agencies, often in cooperation with the USDA Animal and Plant Health Inspection Service (APHIS), monitor population levels and coordinate suppression programs.
The governmental response frequently involves the aerial application of insecticides over rangeland and public land that serve as migration corridors. Diflubenzuron is the preferred chemical for these wide-area treatments, often applied using a Reduced Agent and Area Treatment (RAAT) method. RAAT involves applying the insecticide in alternating treated and untreated swaths, which minimizes the impact on non-target organisms while still suppressing the cricket population through their foraging movements.
Community action and neighbor coordination are important, especially in residential areas. Individual efforts to install barriers or lay bait can be undermined if the adjacent property remains untreated, redirecting the swarm next door. Working together to establish continuous, unbroken slick barriers and coordinating simultaneous bait applications creates a unified defense, preventing crickets from finding gaps in control efforts.