Coulee cricket

The Coulee cricket (Peranabrus scabricollis) is a flightless, robust insect belonging to the family Tettigoniidae. It is characterized by a large, humped pronotum that gives it a distinct appearance.

These crickets are typically dark brown or black, often with a mottled pattern that helps them blend into soil and dry vegetation. Their bodies are protected by tough, chitinous armor.

They do not have functional wings and are incapable of flight. Consequently, they move by hopping or crawling, often migrating in large groups when population densities are high.

Females are equipped with a long, sword-like ovipositor used for laying eggs deep within the soil, providing protection for the next generation throughout the winter months.

In terms of behavior, they are opportunistic omnivores that can become highly destructive to agricultural crops when natural food sources are depleted or population levels spike.

The Coulee cricket is a significant pest of cereal crops, particularly wheat and barley. They consume leaves, stems, and are especially damaging when they feed on maturing grain heads.

Beyond cereals, they can attack a wide variety of legumes and native range plants, making them a problematic polyphagous pest in diverse agricultural landscapes.

Young plants are particularly vulnerable, as the crickets can quickly strip them of foliage, leading to reduced photosynthesis and sometimes total plant loss.

They also cause qualitative damage by contaminating the crop with frass and creating ragged edges on plants, which lowers the overall marketability of the produce.

Large swarms can devastate a field in a matter of days, moving systematically through the crop and leaving behind visible trails of destruction.

The life cycle of Peranabrus scabricollis consists of one generation per year. They overwinter in the egg stage, buried beneath the soil surface.

Nymphs typically emerge in late spring as soil temperatures rise. They undergo several molting stages, growing progressively larger and more voracious with each age.

Adult crickets are most active during the mid-to-late summer months, coinciding with the peak period of grain development and ripening in the fields.

After reaching maturity, they mate and lay eggs, ensuring the continuation of the population for the following year before dying off in the autumn.

Weather conditions, particularly a warm and dry spring, often correlate with higher survival rates for emerging nymphs and subsequent outbreaks.

Early signs of infestation include irregular holes and jagged margins on leaves. In severe cases, the foliage may be entirely stripped, leaving only stalks.

Frass (droppings) accumulation on leaves and soil near the base of the plant is a clear indicator that crickets are feeding in the vicinity.

Observation of the insects themselves is easiest during the cooler parts of the day, as they hide under debris or in dense vegetation during the peak heat of the afternoon.

Visible trails of damage often start at the edge of the field, where populations migrate from surrounding grasslands or uncultivated buffers.

Head damage in cereals, such as missing kernels or partially chewed glumes, is a hallmark sign that the infestation has reached the reproductive stage of the crop.

Tillage practices, such as plowing, can be effective in disrupting the egg-laying sites and exposing eggs to environmental extremes, thereby reducing the population.

Maintaining clean field borders by controlling weeds helps to eliminate the primary habitats and food sources that crickets rely on before moving into the crops.

Chemical control, when necessary, is best applied as a perimeter treatment to stop migrating swarms before they reach the main part of the field.

Biological monitoring and the use of targeted insecticides during the early nymphal stages can help prevent large-scale outbreaks later in the season.

• Early monitoring of field edges for nymph presence.
• Strategic use of chemical barriers on infested perimeters.
• Mechanical soil disturbance to destroy egg reservoirs.