Plathypena

Systematic position. The genus Plathypena belongs to the order Lepidoptera, family Erebidae, and subfamily Hypeninae. Within this genus, Plathypena scabra, commonly known as the green cloverworm, stands out as a significant pest of legume crops. These moths are characterized by their nocturnal activity and the distinct triangular shape of their wings when at rest.

Crops and damage. This pest primarily attacks soybeans, alfalfa, clover, and other leguminous plants. The larvae are voracious leaf-feeders. They consume leaf tissue between the veins, creating a skeletonized appearance. Heavy infestations can lead to significant defoliation, which reduces the plant's ability to photosynthesize and ultimately compromises pod filling and seed quality during the reproductive stages.

Biology and life cycle. Plathypena undergoes complete metamorphosis. Adults are dark-colored moths that lay eggs singly on the undersides of leaves. The larvae go through several instars, with the later instars causing the most damage. Pupation typically occurs within folded leaves or in the top layer of the soil. Depending on the latitude, there can be multiple generations per year, with adults often overwintering in debris or sheltered areas.

Pest status. The pest potential of this insect is highest during mid-to-late summer when soybean plants are in the critical pod-setting phase. While natural enemies such as wasps and predatory bugs often keep populations in check, favorable weather conditions can trigger outbreaks that require professional intervention. Assessing the number of larvae per plant is essential for making informed economic decisions regarding chemical control.

• Regular scouting of fields to monitor larval density.
• Promoting natural biological control through beneficial insect conservation.
• Application of selective insecticides when the economic threshold is exceeded.
• Integration of cultural practices, such as proper crop rotation.
• Utilization of microbial insecticides, specifically those containing Bacillus thuringiensis.