Migratory grasshopper

Systematic position: The migratory grasshopper (Melanoplus sanguinipes) belongs to the order Orthoptera and the family Acrididae. It is one of the most destructive agricultural pests in North America, known for its significant potential to form large swarms and cause widespread economic damage to food production systems.

Crops affected: This species is a generalist feeder with a very broad host range. It infests a wide variety of crops including cereal grains (wheat, barley, oats), maize, soybeans, alfalfa, and numerous vegetable crops. In addition to cultivated plants, they frequently feed on native grasses, significantly reducing available grazing forage for livestock.

Biology and life cycle: The insect typically completes one generation per year. The overwintering stage is the egg, which is laid in the soil by females during late summer and autumn. Upon warming in the spring, the eggs hatch into nymphs, which progress through five distinct developmental instars before reaching the adult winged stage.

Damage and severity: Both nymphs and adults consume plant tissues, leading to leaf stripping and stem damage. The most severe damage occurs when high populations migrate from range lands into neighboring crop fields. Without proper intervention, entire sections of fields can be completely defoliated, resulting in substantial losses of yield and grain quality.

Control measures: Integrated Pest Management (IPM) is essential for controlling this grasshopper. Recommended strategies include:

• Tillage practices that disturb the soil and destroy overwintering eggs.
• Application of approved insecticides at early nymph stages to prevent population outbreaks.
• Monitoring of grasshopper density to determine economic thresholds.
• Maintaining field borders free of weeds to reduce suitable egg-laying sites.