Imported Longhorned Weevil in Soybean
Crop Damage
Imported longhorned weevils (Calomycterus setarius) have been reported in several states in the Midwest, New England, and Mid-Atlantic regions. They are a sporadic soybean pest. Larvae feed on roots but do not cause economic damage. Adults feed along leaf margins, creating ragged edges. As feeding progresses inward, leaves become scalloped, leaving the main veins intact.
Imported longhorned weevil adult.
Natasha Wright, Braman Termite and Pest Elimination, Bugwood.org
Pest Description
Adult weevils are approximately 3/16 inch long, mottled gray-black, and covered with rows of short hairs. They have a characteristic broad snout and long, elbowed antennae. Full-grown larvae are about 1/4 inch long, legless, light yellow, and have several distinct hairs on the head.
Scouting and Management
There are no established scouting or management protocols for imported longhorned weevils. They are attracted to weeds, including bindweed, lambsquarters, morning glory, and several other species, and often cluster in field borders. Because adults cannot fly, movement into soybean fields is slow. Inspect field edges, especially weedy areas, and closely examine nearby soybean rows if weevils are present. If damage is widespread, contact local or state extension specialists for guidance. There are no treatment recommendations for imported longhorned weevils in soybean, as they are sporadic and not known to cause economic damage.
Please contact your agronomist or extension specialist for management information.
Prepared and reviewed by Carol Pilcher and Robert Wright, with support from the United Soybean Board.
Imported longhorned weevil adult.
Gallery image courtesy of Natasha Wright, Braman Termite and Pest Elimination, Bugwood.org.
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