Salt Marsh Moth: What Constitutes a Pest???

Subject: Possibly a Salt Marsh Moth
Location: Coryell County, central Texas
February 3, 2013 1:33 am
This beautiful moth was near our porch light tonight. Is it a Salt Marsh Moth, Estigmene acrea? The Butterflies and Moths of North America website says it’s considered a pest, but it’s gorgeous, regardless. Thank you.
Signature: Ellen

Hi Ellen,
Your identification of the Salt Marsh Moth or Acrea Moth, Estigmene acrea, is correct.  We turned to BugGuide and learned that caterpillar hosts include a wide variety of plants and there is no indication if there is a preferred plant host.  According to BugGuide:  “Larvae feed on a wide variety of mainly weedy plants including pigweed (Amaranthus spp.), anglepod (Gonolobus spp.), Sicklepod (Cassia tora), Dog Fennel (Eupatorium capillifolium), ground cherry (Physalis spp.), and mallow (Anoda spp.), plus crops such as alfalfa, asparagus, bean, beet, cabbage, carrot, celery, clover, corn, cotton, lettuce, onion, pea, potato, soybean, sugarbeet, tobacco, tomato, and turnip. On rare occasions, they also feed on leaves of deciduous trees and shrubs: alder, apple, cherry, elderberry, pear, poplar, and serviceberry, according to Handfield.”  The Butterflies and Moths of North America does indeed state:  “Larvae (Salt Marsh Caterpillars) are pests on many plants” and hosts listed are “Apple trees, cabbage, clover, corn, cotton, peas, potato, tobacco, and other plants.”  We paused to ponder what would make a creature a pest in terms of agriculture.  Creatures that seriously threaten the health of a plant would fall into the pest category, but caterpillars feed on leaves and they really don’t do lasting damage to the plant.  Salt Marsh Caterpillars are general feeders, so they would seem to be just as likely to feed on a crop plant as they would the weeds (unwanted plants) nearby.  We do not believe Salt Marsh Caterpillars make any appreciable economic difference in the agricultural industry, though they might make some plants unappealing looking if there are holes chewed in leaves.  We do not believe Salt Marsh Caterpillars feed in colonies that will defoliate plants, so in our opinion, “pest” is a harsh word to describe them.