Salt marsh moth

The genus Estigmene, part of the Erebidae family and Arctiinae subfamily, is widely recognized for its agricultural impact. These moths are notoriously polyphagous, meaning they can thrive on a diverse array of host plants, which makes them a constant challenge for global agricultural producers.

Host crops typically include a variety of legumes, vegetables, and field crops. The larvae, commonly known as salt marsh caterpillars, are voracious feeders. They rapidly consume foliage, and in cases of high population density, they can cause total defoliation, which severely hampers the photosynthetic process of the crop.

The biological cycle follows a typical metamorphosis: egg, larva, pupa, and adult. Eggs are laid in clusters, usually on the underside of leaves. As the larvae develop, they go through several instars, increasing their food intake significantly with each stage. The speed of the cycle is temperature-dependent, often resulting in multiple overlapping generations per year.

Damage symptoms begin as small holes or skeletonized areas on the leaves. As the larvae mature, they consume entire leaves, leaving only veins or stems. This reduction in leaf area directly translates into reduced yields, stunted plant growth, and sometimes total loss of the crop stand, especially during early developmental stages.

Integrated Pest Management (IPM) is the most effective approach for controlling Estigmene. This involves a combination of strategies:

• Regular field scouting to monitor egg masses and early-stage larvae;
• Implementing cultural practices such as deep plowing to disrupt pupal overwintering sites;
• Using biological controls like microbial insecticides (e.g., Bt);
• Targeted application of synthetic insecticides only when economic thresholds are reached;
• Management of surrounding weeds that serve as alternative host sites.