Soybean looper

Systematic position: The pest belongs to the order Lepidoptera, family Noctuidae. The genus Pseudoplusia, notably Pseudoplusia includens, is recognized globally as a significant defoliating pest of agricultural crops, particularly within the Americas and subtropical regions.

Crops damaged: The soybean looper is a polyphagous insect. Its primary host is soybean, but it also causes significant economic damage to other crops such as tomatoes, lettuce, cotton, tobacco, and various legume species. Due to its broad host range, it represents a persistent challenge for commercial producers.

Biology and lifecycle: The lifecycle progresses through four stages: egg, larva (caterpillar), pupa, and adult moth. Eggs are usually laid singly on the undersides of leaves. The larvae undergo several instars of development over a period of 2 to 4 weeks, feeding intensely before spinning a silken cocoon in which they pupate. The duration of the cycle is highly dependent on ambient temperature.

Nature of damage: Larvae are voracious feeders. In the early stages, they feed on the underside of leaves, creating small holes or "windows." As they grow into older instars, they consume the entire leaf lamina, leaving only the major veins. Severe infestations can cause total defoliation, which severely stunts plant growth and reduces pod filling in soybeans.

Control measures: Management strategies rely on integrated pest management (IPM) practices. Key tactics include:

• Scouting fields regularly using pheromone traps to monitor adult flight.
• Utilizing biological control agents, such as beneficial parasitic wasps and microbial pathogens.
• Applying selective insecticides when the threshold of damage is exceeded.
• Maintaining field hygiene to eliminate alternative host plants and crop residues.