Chrotogonus trachypterus

Chrotogonus trachypterus, commonly known as the grasshopper of the Pyrgomorphidae family, is a small, stout-bodied insect. Adults typically measure between 14 and 20 mm in length.

The insect possesses a characteristic rugose, warty body surface that acts as highly effective camouflage against soil and dry debris. This physical structure makes it hard to detect in agricultural fields.

Its coloration ranges from greyish-brown to dark brown, allowing it to blend seamlessly with the ground. The head is large, and the pronotum often features small spines or projections.

Females are generally larger than males. While they have wings, they are rarely observed flying; instead, they rely on jumping or crawling along the ground as their primary mode of locomotion.

Nymphs resemble smaller, wingless versions of adults. They pass through several developmental stages (instars) before reaching maturity, becoming increasingly destructive as they grow.

This pest is a generalist feeder (polyphage) known to attack a wide variety of crops. It is particularly notorious for damaging germinating seedlings and young plants.

Primary host crops include cotton, wheat, millet, sorghum, and various legumes. In the absence of primary crops, they readily survive on weeds present in the field.

The insects use their chewing mouthparts to gnaw on the edges of leaves, tender stems, and even the growing points of seedlings, often leading to total stand failure.

Damage is most severe during the early growing season. Because they often occur in large numbers, a single infestation can denude an entire plot within a few days.

Secondary damage occurs when feeding wounds expose the plant to soil-borne pathogens, facilitating the entry of fungi and bacteria that cause further decay of the plant.

The life cycle of Chrotogonus trachypterus is heavily influenced by moisture and temperature. High temperatures during late spring and summer trigger peak breeding.

Females lay their egg pods in the upper layers of the soil, often preferring loose or slightly moist ground to ensure successful incubation of the eggs.

The emergence of nymphs usually correlates with the sowing or early development phase of major crops. This synchronicity ensures that plenty of food is available for the growing nymphs.

Multiple generations can occur throughout the year, depending on the climatic conditions of the region, which leads to cumulative damage over the cropping season.

As temperatures begin to drop in late autumn, the insect's activity declines. They prepare for the winter months, often seeking shelter in the soil or under crop residues.

The most visible sign of an infestation is the irregular, ragged edge patterns on the leaves of young seedlings caused by the insect's gnawing activity.

In cases of severe infestation, patches of the field may show completely destroyed plants, leaving behind only the stumps of stems or completely bare soil.

The presence of the insects themselves is an obvious indicator. They are ground-dwellers that jump quickly when disturbed, often burying themselves in loose soil.

Leaves may show heavy scarring, and in some cases, the entire leaf blade might be consumed, leaving only the primary veins or petioles behind.

Observing the soil surface near damaged plants may reveal the characteristic droppings or the disturbed soil texture caused by the insects burrowing into the ground.

Cultural control is essential. Deep plowing during the post-harvest period helps expose egg pods to harsh weather conditions and natural predators, reducing the population.

Maintaining a weed-free field is critical, as weeds serve as a refuge and food source for the pest during the off-season or between different crop plantings.

Chemical control involving systemic or contact insecticides is recommended if the population exceeds the economic threshold, especially on young vulnerable crops.

Poisoned baits containing suitable active ingredients are an efficient way to target the insects directly on the ground while minimizing the impact on the overall environment.

• Regular inter-row cultivation.
• Crop rotation to break the life cycle.
• Monitoring with light traps for adult presence.
• Seed treatment with protective chemicals.