Migratory grasshopper

Systematic position: Melanoplus mexicanus belongs to the order Orthoptera and the family Acrididae. Commonly known as the migratory grasshopper, this species is a significant pest in North American agriculture, recognized for its periodic outbreaks and destructive feeding habits that impact a wide range of botanical species.

Biology and lifecycle: The species undergoes incomplete metamorphosis. It overwinters as eggs buried within the soil inside egg pods. Larvae (nymphs) emerge in spring as the soil temperatures rise. Throughout their five nymphal stages, they are highly mobile and voracious feeders, eventually molting into winged adults capable of long-distance dispersal and migration to greener feeding grounds.

Host plants and damage: As a polyphagous insect, it causes damage to numerous crops, including wheat, corn, alfalfa, soybeans, and vegetables. The damage involves aggressive defoliation, where the pest strips the leaves, leaving only veins or completely devouring seedlings. In cases of high infestation, the pest can consume the entire canopy of a crop, leading to catastrophic yield losses.

• Severe defoliation leading to stunted plant growth.
• Destruction of young seedlings resulting in plant death.
• Direct injury to grain heads and fruits, impacting commercial value.
• Reduction of livestock forage quality in pasture lands.

Control measures: Managing this pest requires an integrated approach. Cultural controls such as autumn tillage help disrupt the overwintering egg beds in the soil. During outbreaks, chemical control is often necessary. The application of contact or systemic insecticides should be timed during the early nymphal stages for maximum efficacy. Monitoring programs and timely field scouting are essential to determine the economic threshold for intervention.